How do expert writers avoid using "I" when they have to refer to themselves in their article?

Question: How do competent authors, in a refined and perhaps (slightly) formal way, refer to themselves without saying I? I've seen the term "this writer" somewhere. How is it with a native? Are there other terms that are a little bit more formal and delicate than I is?
Comment: "one", possibly. "*One does not simply refer to themselves*"
Comment: My point was that it's bad style for a single person to write "as we showed in an earlier paper" or "as the author has shown previously". Instead, write either "as I have shown previously" or just "for a proof of ... see [1]". "We will see in the next section" is fine, though, as it includes the readers.
Comment: One of the best-written mathematics books I know (Wilfrid Hodges, Model Theory) starts with a section on conventions used in the book, as is usual. But this one includes the following gem: "'I' means 'I' and 'we' means 'we'." And the author really uses the two pronouns in this way without any attempts to hide his personality. Maybe this approach only works in mathematics and hard science, where people sometimes say things such as: "You are right, yesterday you proved the main theorem in my book is wrong and today I found my mistake." And it's not the end of the world, either.
Comment: In journalism and reporting, they sometimes use "your correspondent" or "your [word that describes journalist on reporting duty]"
Comment: Don't be afraid to use the right word in the right situation. Sometimes that word is "I." Just don't talk about yourself so much in your papers.
Comment: @HansAdler ; I guess , yes, it must have something to do with the "type" of the material. Anyway I'm gradually coming up with the conclusion that it's a matter of both context and taste. It emerges that some people do not really like anything in their written work that betrays, so to speak, any signs of (extra) humbleness. When it comes to me, to be honest, I believe using "I", more often than not,ends up in infusing an unspoken sense of the writer's self-centeredness into readers.
Answer: Many competent writers will challenge the assertion that "the perpendicular pronoun" (I) really needs to be avoided. Others seem to believe that only third person is acceptable, or that no person should ever be mentioned unless specifically talking about people.
My own take is that this is all a matter of style, and whatever you pick -- as long as it sounds natural and you're consistent about it -- is probably fine. If I'm writing for my employer, I'll follow my employer's style guidelines. If I'm writing for publication, I'll follow the publication's preferences. If I'm writing without those constraints, my writing is generally only slightly more formal than my speech.
Answer: Competence precludes finding oneself needing to mean "I" but having to say "this writer" - or, variously:

the author
your correspondent
this ink-stained wretch (please, no!)

TBH, the form hardly matters - silk purses and sow's ears, etc.
Comment: Exactly. A genuinely expert writer avoids introducing himself into a literary context where his presence is deprecated. An essay is like any other social occasion. If you belong there, you may introduce yourself in the first person without offense. If you don't belong there, you shouldn't be trying to sneak in unnoticed by pretending to be somebody else.
Comment: I used to favor "your humble narrator" for a while. Then I decided I wasn't all that humble and often wasn't narrating.
Comment: I agree with StoneyB.  If I have a reason to write about myself, then I'll use "I" (and "me", "my", etc.).  If I don't have a reason to write about myself, I won't.
Answer: In science, it is quite common to use "we" instead of "I" even if there is only one author.
Comment: In maths, "we can see" or whatever can imply "You, the reader, and I", which I think is quite nice.
Comment: True, that is another meaning of the scientific "we".
Comment: In science it is common because most papers are published by two or more authors! So the impression that "we" is common might be a false one. In my experience, single authors always refer to themselves as "I" in the natural sciences.
Comment: There definitely are single-author papers which use "we". However, people sometimes feel uncomfortable using this form, and change everything to passive voice to avoid it.
Comment: Formally this is called 'royal we', which has uncomfortably arrogant connotations, although I agree, it's used.
Comment: @painfulenglish,  [Citation needed](http://xkcd.com/285) for *"In science, it is quite common to use "we" instead of "I""*.
Answer: Use of pronouns like "I" and "me" in a narrative will tend to cast the writer as the protagonist.  Use of other forms such as "yours truly" or non-reflexive "myself" tends to cast the author into a "supporting character" role.
Suppose someone is writing about Mr. Smith's performance in a chess tournament and, after saying "In round one, Mr. Smith played against Alec Jones" and describing his performance in that round, went on to say "In round two, Mr. Smith played against me".  A reader might expect the description of the round to be focused on the writer, rather than on Mr. Smith.  If instead the text had been "In round two, Mr. Smith played against yours truly."
Some people cringe at non-reflexive usages of "myself".  I personally don't find them objectionable when used in either the imperative or passive voice, with the purpose of suggesting semantic equivalence between the person writing or speaking and others.  For example, if Mr. Smith asks people "Please submit reports to Mrs. Robinson, Mrs. Jones, or to me", that would suggest that submissions to him would be perceived differently.  Using the non-reflexive "...or to myself" would suggest that the set of people to whom forms may be submitted includes him, but he has no special significance within that set.
Even though the non-reflexive "myself" is often useful, there are many places where it just doesn't work, especially with the active voice, or when used with verbs that would be amenable to reflexive usage.  For narrative situations, "yours truly" is concise but effective; it conveys no implication that the character in the story were affected by the fact that they would later be written about.  By contrast, "this author" implies that the writer's status as an author was significant to the events described.
What's important is to recognize that there are many ways an author can refer to himself, and usage of forms other than simple first-person pronouns is not merely a matter of being "cute", but often carries somewhat different meanings and implications.
Comment: If in the second round, Mr. Smith played against the author, any circumlocution like "yours truly" or even "the author" will sound like just that: a circumlocution, and thus awkward and unprofessional. In such a situation, any semi-competent author will use "me", period end of story.
Comment: Is there any source for acceptability of a non-reflexive meaning of "myself"?
Answer: It seems to depend on the context, and even more so on the type of writing.  Some answers have addressed it, it's strange that none have aggregated different scenarios where one would want to avoid referring to oneself directly.

In journalism, it's generally frowned upon to use "I."  I've seen many cases of "your correspondent" in most of the articles I read.  "Your author" is also possible, though maybe not so much for journalism.
In most scientific cases, authors sometimes avoid using a reference to themselves entirely by using the passive voice.  I found that this is common here.
In other academic scenarios, many do use "I" but I've seen many research papers which use "we" even when referring to the single author.  Mathematic proofs, for example, always say "we know that..." or "we can see from ... that..."

Of course it's always good to do a bit of research on the particular scenario in which you are.
Comment: As commented above, the mathematical "we" means "the author and the reader", so it's certainly appropriate even with only one author.
Comment: I disagree. Both meanings exists. When I write "We studied problem x" in a paper, I mean me and possibly my co-authors, but certainly not the reader. I'm quite sure many other scientists use "we" in this way.
Answer: I see two main contexts:

The author of the work is also relevant to the subject under discussion. Then the author should use the third person and a name. "Reports must be submitted in triplicate to both Itsme and Steve Jessop". "Mr. Jessop has responsibility for X, whereas Itsme handles Y". It might matter which of us wrote that text, we might have collaborated on it. Someone who cares can check the top of the document, but it's not relevant to the matter at hand, so let's not mess about identifying professional responsibilities relative to authorship of the document.
The author wants to personalize the authorial voice. This generally isn't what you want in formal writing, but might be done from an excess of ego or an excess of honesty that you're writing a personal opinion or experience.

In this case, assuming you want to avoid "I", then you say "the author", "this author", "this reviewer", "this observer", and so on. Identify the role whose point of view you're trying to inject. So for example a journalist who attended a political event might first lay out the facts in the usual way, and then mention "this observer" when giving a more subjective view: "Following the speeches a fistfight occurred, but this observer was unable to determine who started it" makes clear that even to those in the room it was not necessarily obvious what was going on.
Whether you should want to avoid "I" at all is probably outside the scope of the question, but personally I think it depends in large part on whether you think the reader knows or cares who is addressing them. Extreme case, a newspaper report with no by-line shouldn't use "I", because the reader can't know who that is even if they want to. Even with a by-line, a reporter's style avoids it. An opinion piece has a lot more scope to use "I".
Comment: For things like memos which, while written by people, are supposed to speak in the voice of the company those people are representing, it is entirely appropriate for the author to refer to himself by name just as would anyone else.  In cases where the author has a personal voice, however, such a thing might prompt readers to wonder whether the author and the person identified were the same person, or whether the text was actually written by the claimed author; such distractions might be avoided if you refer to yourself as "Steve Jessop (yours truly)".
Comment: Well, "yours truly" to mean "me" is awful, but that's a matter of taste since it's entirely comprehensible. Anyway in writing it's just an indirect way of saying "the author" or "your correspondent", i.e. it's the person who would sign off a letter "yours truly".
Answer: This writer is correct.
For example:

Exercise has many benefits. Proponents of exercise find there is a large variety of exercise options to fit different lifestyles. Barack Obama goes running in the morning. Jane Doe attends a weekly dancing class. I myself do press ups and stomach crunches in between writing stints through out the day.

The writer can remove the first person perspective by replace 'I myself' with 'this writer'.

Exercise has many benefits. Proponents of exercise find there is a large variety of exercise options to fit different lifestyles. Barack Obama goes running in the morning. Jane Doe attends a weekly dancing class.This writer does press ups and stomach crunches in between writing stints through his writing day.
Comment: What evidence do you have to proclaim it as "correct"?
Comment: Why not, "Press ups and stomach crunches can be accomplished in between writing stints throughout the day"? Or, "in between performing sedentary tasks..."?
Answer: In the natural sciences, the use of the personal pronouns "I" (for one author) and "we" (for two or more authors) is perfectly fine. In fact, you must use these pronouns, if you refer to yourself!
For example the Manual (2009) of the American Psychological Association clearly states (pp. 69-70):

Attribution. Inappropriately or illogically attribution action in an effort to be objective can be misleading. Examples of undesirable attribution include use of the third person, anthropomorphism, and use of the editorial we.
Third person. To avoid ambiguity, use a personal pronoun rather than the thrid person when describing steps taken in your experiment.
Correct:
We reviewed the literature.
Incorrect:
The authors reviewed the literature.
Anthropomorphism. Do not attribute human characteristics to animals or to inanimate sources.
Correct:
The staff for the community program was persuaded to allow ...
Incorrect:
The community program was persuaded to allow ...
An experiment cannot attempt to demonstrate, control unwanted variables, or interpret findings, nor can tables or figures compare (all of these can, however, show or indicate). Use a pronoun or an appropriate noun as the subject of these verbs. I or we (meaning the author or authors) can replace the experiment.
Editorial we. For clarity, restrict your use of we to refer only to yourself and your coauthors (use I if you are the sole author of the paper). Broader uses of we may leave your readers wondering to whom you are referring; instead substitute an appropriate noun or clarify your usage:
Correct:
As behaviorists, we tend to dispute ...
Incorrect:
We  tend to dispute ...

The fundamental rule of all APA syle are "precision and clarity" (p. 68):
"Make certain that every word means exactly what you intend it to mean."

See also this post in the APA Style Blog: Use of First Person in APA Style.
Answer: If the work has a list of references, then refer one can refer to the reference as if referring to any one else's reference.  As an alternative, one can refer to the name of the content of what they want to reference instead of using the attribution of the content's creator (ie, "I").
Answer: In legal writing there is an easy answer: you refer to the roles played rather than the individuals who undertook them. So if you are writing a brief and complaining that the judge did something you didn't like, you wouldn't write, "the judge did not let me present evidence" but, "counsel for plaintiff was prevented from presenting evidence." Because in this context personalities do not matter.
While this question is directed towards non-fiction, the winds of what the French call "autofiction" are blowing and I think we will see a greater use of the first person in all types of writing. Even though Rimbaud famously wrote, "Je est un autre." (I is someone else.)
Answer: If the writer is truly an expert, then they refer to themselves so enigmatically that they set the 2000-year-old standard for how to subtly promote oneself:
http://en.wikipedia.org/wiki/Disciple_whom_Jesus_loved
Answer: Use "I" all you want. I was taught the same thing in school: "don't use "I" because of whatever". That's total BS.
If you haven't already, read "Journey to the End of the Night" by Celine, one of the best books in French literature. You'll see how you can write a masterpiece not just using "I" everywhere, but also making intentional grammar/syntax errors in every other sentence!
PS: the book is translated from the French at Project Nutenberg, for free...
Comment: Welcome to ELU.SE. I don't believe it's all that convincing to explain something you believe to be the case in English by referring to French literature, I'm afraid. "Don't bother" might be a reasonable answer, but needs some English substantiation.
Comment: The pleasure is all mine. I am afraid that you are wrong though. The fact that the book is French is completely irrelevant for this conversation. It is for the exact same reason the word "I" should be avoided in French as it is in English. Furthermore, I was not referring to "Voyage jusqu'au bout de la nuit", but to its English translation "Journey to the End of the Night".


What happens to old transactions in case of a fork?

Question: I'm confused about forking. What happens to the 'old' version of a blockchain and related transactions/data in case of a fork. Can they still be deleted or does the new branch still depend on them to ensure continuity?
Comment: I'm curious about this in relation to both soft and hard forks. Thanks!
Comment: What type of fork are you asking about?  There are short-lived forks where some blocks are orphaned (made stale) either accidentally or on purpose; there are soft forks that change the consensus rules in a backwards compatible way; and there are hard forks that change the consensus rules in a backwards-incompatible way.
Answer:
What happens to the 'old' version of a blockchain and related transactions/data in case of a fork. Can they still be deleted

In the case of a soft fork, historic data must be kept.  In the case of a hard fork, it's not strictly necessary to keep historic data but it is almost always retained.
Going in to a bit more detail: a soft fork changes the rules everyone follows in a backwards-compatible way by only making the rules more strict.  For example, miners have access to a field called the "coinbase" into which they used to be able to put any arbitrary series of 2 to 100 bytes; later a rule was added that specified in the BIP34 soft fork that the first few bytes of that field had to be the current block's height (distance from the first block).  This is more strict, so everyone who follows the new rule also automatically follows the old rules.  This is backwards compatible because anyone who followed the old rules and isn't already violating the new rules can continue to use their software as normal.
However, for that backwards compatibility to hold true, the data available in the block chain has to not only remain available but stay in basically the same format.  You can sometimes do tricks with that, as segwit did by moving signatures to a new field in transactions, but there's a limit to the scope of changes you can reasonably make.
For hard forks, there rules are changed in a backwards-incompatible way so everyone needs to upgrade anyway.  This gives you a blank slate upon which to make any change to the system you want.  Regarding old block chain history, what you can do is commit to the current state of the system and throw out all history used to arrive at that state.
For example, imagine Alice mines a bitcoin and then pays that bitcoin to Bob.  The block chain will include both the mining transaction and the payment transaction, but if everyone is upgrading anyway, it's simple to just say "Bob starts with 1 bitcoin" and throw away Alice's mining transaction.
If you were to throw away historic data and keep just the current state after a Bitcoin hard fork, you could reduce the current block chain size by about 98%, down to just a few gigabytes.
However, I'm not aware of any hard fork of Bitcoin or an altcoin that ever threw out the historic data and simply committed to the current state.  I don't know why that's the case.
Comment: If you discard the earlier transactoin and start with new state, wouldnt that effect the 1:1 coin distribution scheme that comes with each hard fork.
Answer: "What happens to old transactions in case of a fork?" nothing. the "old" transactions will still be available. otherwise it is not a fork. both branches of the fork will have the same history until the moment of the fork.
"Can they still be deleted or does the new branch still depend on them to ensure continuity?" today's state is that transactions will not be deleted in general. the old transactions are required to ensure integrity because you need them to track the history of your bitcoins and to re-validate the hash-values of all blocks.


Why does it get darker in Israel quicker?

Question: Why is it that it gets darker in Eretz Yisroel quicker than in the USA, making for a shorter Ben Hash'moshos?
Comment: While I see value in this question, it's not clear to me how this is more on topic than [this question](http://judaism.stackexchange.com/q/17306/5).
Answer: Generally (without considering many other factors which may be involved) the closer the latitude is to the poles [i.e. the absolute value of the latitude is greater], the longer the sunset.
(see table at this pdf (last page) and this piece of mail for more factors)
Therefore:
Latitude at NY, NY = 40.7
Latitude at Jerusalem, IL = 31.78
NY, NY is closer to the poles, hence longer sunset.
Hope I understood the question and got the right answer...
Comment: To elaborate on yydl's answer: The level of darkness in the sky at a particular moment depends on the sun's position below the horizon, which is measured in degrees. Now, unless you are at the equator, the sun always sets at an angle, corresponding to your latitude (e.g., in NY the path will be inclined 40 degrees from vertical). The higher the latitude, the larger the angle - and the larger the angle, the longer it will take for the sun to reach a given number of degrees below the horizon. It's like crossing a street -- if you cross at an angle, it will take longer to get to the other side.
Comment: @Dave: I like that answer. You should make it your own answer, so that I can vote you up and give you reputation points.
Comment: @Chanoch - thanks, but it's fine this way.


What are the disadvantages of not warming up?

Question: In other words, what are the disadvantages of playing at the limit of your technical abilities straight away, without warming up first? Why is warming up usually recommended?
Answer: Many musicians use a warmup routine that is learned off by heart. They can tell when something feels wrong, but more importantly, it can be used as a very simple way to become ready and get into the groove or flow.
Physically it's the same principle as going to the gym for a workout. If you don't warm up first, you may find your joints are stiff, your movements slower and less precise than you may like, and you may not be able to feel as much as you should.
Warming up can relax tissues, pump oxygen into muscles and tissues, and get you ready for movement.
Not warming up can cause pain and damage - sometimes even permanent - to tissues and joints.
tl;dr - always warm up, even if only for 5 minutes
Answer:
Why is warming up usually recommended?

To play them well, all instruments (including the voice) require musicians to use their muscles, tendons and nerves in ways not normally used in everyday life.
Because that's so, most musicians, unless they are unusually facile or always ready to play because they play so much (John Coltrane reputedly was almost constantly playing, except when he had to eat or use the toilet - he was probably always "warmed up") , need a warm-up period to stretch and bring better muscle tone, blood circulation and nervous stimulus to those parts of the body used in playing.
Often a performer will do a warm-up set right before a performance. When that entails too much time and trouble, sometimes performers will begin their performance with a "warm up piece" that isn't particularly challenging but allows them to stretch and play in different ways that will be required during the rest of performance.
Aside from actual warm up playing, there are also various sorts of exercises and stretching routines that musicians may do before playing.
Here's some good information about this point:
OUR GO-TO ROUTINE: 10 ESSENTIAL STRETCHES FOR MUSICIANS

Many people may not understand how physically demanding playing music
  can be, especially for those of us who have to hold the weight of an
  instrument through a long performance (we're looking at you, marching
  euphoniums), or who often play lengthy, complex works solo (hello,
  concert pianists and strings musicians).
Keeping your body in good physical shape is essential to playing your
  best, no matter your musical instruments. Endurance, control and
  overall flexibility will aid in preventing common injuries like
  tendonitis and muscle sprains, improve your posture, and ultimately
  help you to become a stronger musician. In addition to your regular
  cardiovascular and strength-building exercises, the following are
  helpful stretches for musicians to complete prior to every practice
  and performance. Think of this routine as essential prep prior to
  playing, just as you'd warm up and tune your instrument...
Neck/Shoulder Movements... Elbow Movements... Wrist and Finger
  Movements...

It's no different than an athlete going through a warm-up routine before competing. Playing most instruments proficiently is essentially a specialized form of athletic activity, and to be at your best it requires the same sort of preparation/warming up as any other form of athletics.
Baseball players play exhibition games in spring training, take batting practice and warm up in the bullpen before a game, and do stretches between innings and take practice swings with a weighted bat while standing in the on-deck circle. Most serious/professional musicians have similar routines, depending somewhat on the situation, as @LaurencePayne has mentioned in his answer:

What are the disadvantages of not warming up?

Quoting the above page:

Warming up aids in preventing common injuries like tendonitis and
  muscle sprains, improve your posture, and ultimately help you to
  become a stronger musician.

So if you don't warm up, you're at risk for those maladies.
It also helps you play better when it's time to perform - your body is ready to go. If you take the stage "cold", your chances of hitting your stride right away are diminished - and that's not good for your performance or your reputation.
I live in NYC. My Dr. shares an office with a physical therapist. I was discussing with him some hand and back problems I was suffering from due to playing (EBG). Doctor told me that most of his office mate's clientèle are professional musicians, who need PT because of the numerous joint, muscle and back problems that arise from their constant work as musicians.
Warming up helps to minimize such problems, but they remain an occupational hazard for many musicians playing at the highest levels of professionalism - full time concert and jazz musicians, for example.

In other words, what are the disadvantages of playing at the limit of your technical abilities straight away, without warming up first?

As far as that goes, the disadvantage is that if you play without warming up, you will not be able to play at the limit of your technical abilities straight away, and if you try to do so, you could injure yourself, just like baseball player can tear his shoulder if he walks in off the street and takes a home run swing at a 100 MPH fast ball.
You could also end up performing poorly, compromising your show and your reputation, as mentioned - nothing worse than opening with your signature riff, but failing to execute it correctly because you're not warmed up.
Answer: As a brass player, 'warming up' is partly a literal description - until the instrument is at the temperature of your breath, it won't be in tune!  Beyond that, some players seem able to jump straight in to performance mode, others benefit from some 'limbering up' exercises.  Personally, I play a few phrases after which I can either say 'that's fine!' and carry on with the gig or 'bit rough today - better play some long notes and lip slurs!'
As a pianist, I find it much the same.  Not all gigs are technically demanding. Some days the fingers are 'working well'.  On others they feel like a bunch of sausages and some exercises are called for.
Answer: Warming up seems to be an individual thing. Some  like to warm up before the performance, others design their set list to begin with easier pieces and warm up while actually performing, but either way most will agree the performance feels more comfortable and flows more naturally after they've warmed up. For singers, it helps clear out phlegm and stretches the vocal chords and helps extend range by a step or two, and makes pitch control easier to accomplish. Finger exercises on a fret board or keyboard help loosen hands that may feel stiff. No matter what instrument, warming up can help get mental concentration on the task at hand. There are more advantages I'm sure. The disadvantages are that you may not have these things going for you if you choose not to allow time for warmup.
Answer: It helps to open up your airways and anything stuck in your throat like mucus or phlegm especially if you are a singer and need to hit high notes


What are the advantages and disadvantages to using a game engine?

Question: How do I know whether or not to use a game engine? I want to make a relatively complex 2D game for Android. What factors should I weigh to decide whether to find, install and learn a game engine or just do everything manually?
Comment: Not sure if game-design is the best tag, here; but engine has been blacklisted. This question should probably just be deleted.
Answer: Advantages:

Most if not all of the coding is done for you, so all you have to worry about is content, level layout, etc.
Along those lines, memory management, asset loading, lighting (in complex engines), etc has all been designed and tested thoroughly (hopefully).
As mentioned below, if the engine is cross platform you will have to do little to no work to port your game.

Disadvantages:

If you are modifying anything, you now need to become familiar with a new codebase.
If there is a bug in the engine, unless it is open source you can't fix it.
The engine was not designed specifically for your game, so it may be less efficient than code you write specifically for your game.
Game engines generally are not free.
If a game is small, the overhead of using an engine may not be worth the time invested to write code yourself.
If your game engine also has any editors or tools, you will have to build and test those as well before turning them over to artists or relying on them yourself.

Don't let the fact that the list of disadvantages is longer: when the time spent coding and testing all the systems you need is too long for your production cycle, or if you have more skill with art than code, using a game engine is definitely a good idea.
A comparison of game engines is in the works in this question: Pro's and Con's of Various 3D Game Engines
Comment: This is a pretty good answer overall, but I furrowed my brow at the very first sentence. I would strongly suggest rewording "Most if not all of the coding is done for you" to "Most of the low-level coding is done for you"; it is misleading to the point of irresponsible to perpetuate the myth of "make a game no coding required!"
Comment: Also, the engine might restrict what you can do easily - for example, just about many don't support Minecraft or Dwarf-Fortress-style modifiable terrain. Which is fine for games that don't need it, but good luck making a Minecraft clone with one.
Answer: In my case, I spent a lot of time (months) floundering around getting nothing done because of game engines. I now typically avoid them like the plague, though I understand they should be used wisely and in moderation.
For me, I'd get obsessed over all the possibilities! Looking at a long list of features in engine X, it's like "Wow I could do all this! My game could be great!" So I'd download it, run the demos and be dazzled by those features in action, etc. Then I'd create a new project in my IDE and wouldn't know where to start. I'd write some code, I might learn from and base it off of the demo projects, but those were just demos.
I didn't know how to start from nothing and make something. I didn't know the first step. I loved the idea of an engine, it impressed me and got me motivated to make something, but my knowledge of actual development was so limited that even after knowing how to add the engine to the build path, and maybe writing a few lines to start the engine and then shut it down again, beyond that I never made anything worthwhile.
I'm much more of a baby step kind of person. I'd rather make my own game one step at a time, refactoring out useful functions and collecting those functions into a library which one day I might consider an "engine". So for now, I avoid the engine hype and just stick with the low-level stuff.
And engines do have their place. If you find an engine and think to yourself, "This is exactly what I would write! They've already done the work for me, I don't have to reinvent the wheel, and I know exactly how to hook it into the game that I've already started [or at least fully planned and am ready to start]" then it's probably a good fit. You'll know exactly how to use it, and how to write your own code to use the engine to create something useful. But if you get an engine just cause it has everything but the kitchen sink and you think you're standing on the shoulders of giants, you're very mistaken. You have a giant standing in front of you, and you need to climb up to its shoulders.
So the huge disadvantage for me: don't get caught up in all the things you could do. Whatever engine you might choose, it will have tons of potential. But if you don't know how to actually harness the potential, if it doesn't make your live easier or help you get your work done, then why are you using it?
Answer: The biggest disadvantage of a game engine is that you have to learn it. If you're new to programming in general, that may still be faster than learning to write code to do all the stuff that an engine handles for you out of the box, but if you're experienced then it costs you no time to sit down and start coding, but a fair amount of up-front time to learn your way around an unfamiliar engine.
Biggest thing to look for is support, because game engines are not perfect and they do not read your mind, and you WILL get stuck on SOMETHING at some point. So:

Is there documentation?
Is the documentation actually any
good?
Is there technical support (generally not, unless you're paying for it)? What's the turnaround time?
Are there community forums where you can post questions and get real answers?
Are there tutorials that show you how to start using the engine? Is sample source code included? How useful do you find these in getting up to speed?
Comment: +1 for putting documentation prominently up front ... that's where many open source game engines fail
Answer: As somebody who has a lot of software development experience and who only really tried to develop a game from scratch recently, here is my 2 cents.
The answers so far have provided long lists of pros and cons. I will provide what for me is the most important reason NOT to use a game engine. As I took on the task of learning to write a game purely for challenge and reward I decided to do it from scratch with no engine, just OpenGL and SDL, because I wanted to learn everything above that level of abstraction. At no stage have I regretted that decision. My game is a nice scrolling version of 2D Asteroids, basic but smooth. I am not trying to compete with vastly superior games, but I do distribute my game and people have enjoyed playing it. I will take the same approach in making the game multi player. This is a huge challenge and using libraries might make it easier, but I my goal is not to make it easy. My goal is to learn, and for me it is a part time activity, so I do not have a lot of time and progress is slow. But I have my reasons for this approach. Call it "higher learning".
So, answer your own question, do you want to learn how to do the things that the game engine instead does for you for the benefits that this learning might bring? If so, do not use a game engine.
Answer: You need to detail what you mean by "complex". A good game engine takes care of all the following:

Rendering on a stable framerate
Input handling
User interface
Sounds/music
Resource management (images, sound, data files)
Saving/loading your game
Physics (2d or 3d)

Think to yourself, do I know how to code each of these? How long will I take to program each, and how long will I take to learn how to make an engine do each of these?
Answer: The biggest advantage: a lot of things are done for you.  You don't have to keep re-inventing the wheel.
Another advantage: The game engine might also be cross-platform (Unity).
Disadvantages?  Control?  The engine is taking care of some things for you (such as rendering) so if it has bugs or performance issues, then you can't simply fix it yourself.


Estimating when the development team won't estimate

Question: I'm new to a situation where a development team refuse to estimate anything until they have a fully defined spec. My angle to obtain estimates is to provide just enough of a spec so they can provide an estimate that has a degree of confidence behind it for e.g. 6 months development time plus or minus 10%. Then I want to refine it over time and set the stakeholders expectations so that they know the estimate will improve. What other techniques could be used in a situation such as this where a lot of discovery is required up front on a large project with a team that pushes to only estimate when they have everything.
Comment: Being on the development side I am also hesitant to give estimates for something not well defined.  I have often seen "estimates" turn into commitments, so my initial thought would be that 6.5 months go by and I'm going to now have to sit in meetings explaining why the project I "promised" to get done still isn't done.  If you still really want to get an estimate out of them, I'd suggest being very clear about what the purpose is and what the ramifications are if that date is not met.  If there are no ramifications, then one starts to wonder what the point of the estimate was.
Comment: Personally, I think that if your team **won't** estimate then you have a big problem. Glen Alleman has a good blog post on the value of even simple estimating here: http://herdingcats.typepad.com/my_weblog/2013/08/how-to-estimate-almost-any-software-deliverable.html
Answer: Per the Cone of Uncertainty, you won't be able to get estimates that have deviations of plus/minus 10% until much later in the project, at least after requirements engineering is complete. For a more agile approach, you would be able to estimate the sprint within this amount of accuracy after detailing the requirements to be implemented in the sprint. For a more plan driven approach, you need to finalize the spec first and even get into system design before you approach this level of certainty. The team also needs to realize this - it's very much acceptable (and well documented by experts such as Barry Boehm and Steve McConnell) for estimates to vary by 200-400% if you just have a concept and a portion of the requirements.
If you are looking for estimation techniques, there are plenty. If your development team consists of experts in the technology and domain, consider Wideband Delphi. It was first described in Software Engineering Economics. The idea is that you get your experts and have them estimate, then discuss and refine their estimates to come to a concensus. It's rather similar to techniques such as planning poker from Extreme Programming. Steve McConnell's Software Estimation: Demystifying the Black Art discusses a number of other techniques and tools for estimation, as well as working with both clients and development teams on estimates, schedules, and deadlines. Although it's geared toward project managers and technical leads, it is consumable by developers as well and I would highly recommend a copy of it.
For overcoming the team's lack of desire to estimate without a spec, I would work with them to explain why it is important that they at least try, even though you know there will be great uncertainty. This is a conversation and even a negotiation to come to an agreement, and there have been many books written on these subjects, and I have to recommend Getting to Yes, Getting Past No, and Difficult Conversations as three leading books on how to have these conversations and discussions.
Comment: +1 for a great summary of 'ways of estimating' and plus/minus 10% won't be possible very early. I'd like to make a point explicit here - the 'metric' required for estimation (i.e., SLOC/FP/Story, use-case points etc.,) may govern the choice of technique - estimating SLOCs maybe very problematic if multiple technologies/languages are involved. FPs are not too easy either - story points would be good even if they are very early. It's the team 'velocity' that would normalize the initial guestimate of time to complete. So choose the approach wisely and weigh its pros/cons before doing so :)
Answer: First, it is a safe assumption that in software development industry you won't have precise estimates if you trying to plan 6 months ahead.
Second, despite of all the uncertainty of half-year-long estimates, and even more uncertainty attached to estimating incomplete or vague requirements, in vast majority of cases stakeholders need to know a general time span and general cost of a project. Is it going to take days, weeks, months or years? Do we need one developer, whole team, a few teams or the whole division? These questions are always valid, even if your approach is that you avoid estimating whenever possible.
In such case I would start with trying to understand why a development team refuses to estimate before full specs are delivered. I mean you will address the situation differently when they actually believe they are going to have their estimates right when they get the full specs than you will if they refuse to estimate as they've been constantly hit because they didn't have their estimates perfect.
Either way, to have anything to start with I'd ask the team for just a coarse-grained estimate, also known as wild ass guess, just for the sake of building general insight how much it can take to build the whole thing. Note: I would go either with multiple-point estimate, meaning it would take something between 3 and 6 months, or estimate with probability attached to it, meaning we have about 80% chance to complete it in 5 months.
Remember: development team has to be sure that if they are wrong, for whatever reasons, on this coarse-grained estimate no one is going to shot them. Otherwise they'd refuse to make any estimates at all.
Then your actions would depend on a situation:

If the team believes that they can deliver perfect estimates if the specs are detailed enough I'd try to deliver such specs but gradually. Only one part of the project, one that the team is going to work on next, at time. At the same time I'd try to educate them that requirements are changing over time and even if you had full specs at the beginning of the project there wouldn't be much of value of even the perfect estimate as conditions would change, thus estimates would need to follow.
If the team had bad experience with their previous estimates, I'd try to avoid estimating at all, besides coarse-grained ones that is. To give you insight how you're doing I'd focus on completing specific features as soon as possible and verifying how you're doing against the plan. One of examples of such approach can be measuring percent complete. This would allow you to discuss with stakeholders progress of the project and steer their expectations.
In each case I would gather and use historical data, regarding how fast the work is being done, what is the pace of the team etc. Depending on a method you choose it can be called velocity, throughput, etc but either way you want to know how many features of roughly this or that size you can build in given time. It means that you need to use some method of sizing features, for example T-shirt sizing (S, M, L, XL, XXL), and then you need to gather data on how much it took to build the feature. I would also add how much time elapsed since you started working on tasks until it was done (lead time), as opposed to how much real work was done on the feature. Knowing that data and learning about trends can help you to tell how your team is doing even if they don't estimate at all or they estimates are worthless.
Comment: I disagree with avoiding estimation. You should be estimating at the appropriate granularity for the given information, since the only way to improve is to continually develop an estimate, perform the work, and determine why the estimate and actual times vary and what to do about it. If you have had problems with previous estimation attempts, consider those when presenting estimates to clients or when building schedules by, for example, adding a small amount of variance (team says 75% confidence, call it 70% confidence when building the schedule, for example).
Comment: @Thomas - Whats the point of estimation? To get insight how much a project is going to take/cost you. Consider you can get this insight basing on historical data and little or no estimation effort at all. Now, again, what's the point of estimation in this case? We know what we wanted. Estimation shouldn't be done just for the sake of estimating. Think of value you get from this activity.
Comment: Using historical data is a commonly used estimation technique that forms the basis of PROBE, Evidence-Based Scheduling, COCOMO, Wideband Delphi, and Planning Poker. You can, and should, use historical data for the initial estimates, but revise those estimates based on current project factors, ranging from team size to familiarity with technology to the projected effort/week. PSP Level 2 and CMMI Levels 4 and 5 call for continuous process improvement, including improving estimation. If you don't appropriately track and analyze estimates for accuracy, you can not meet these requirements.
Answer: If the team doesn't feel like they have enough information to estimate, you should probably listen to them. Especially if you're trying to get +/- 10% on something the size of 6 months. Talk to them and see if there are specific concerns they think need to be addressed, or if they feel like there is insufficient information across the board.
It is possible (even likely) that the team has been asked to do estimates like this in the past and has gotten burned by it. They've likely seen instances where lack of some details in the requirements has lead to drastically different understanding between what they thought needed to be done and what the stakeholders actually expected.
If you haven't already done so, consider spending a couple days putting together story maps, including stakeholders as well as at least some portion of the development team. The development team can ask the questions where they see holes, and the stakeholders can fill them in. It helps ensure that everyone has the same vision of what is actually expected to be accomplished.
If the team thinks there are still significant risks, be willing to accept that either +/- 10% may not be achievable, or you are going to have to decide whether you can ensure that risks and scope are managed correctly during development.
Answer: You are asking the team to make cost estimates when they do not have enough information. To do this, they will have to make assumptions, and they are refusing to do this, because it has bitten them in the ass.
There are two ways to solve this. One way is to make sure it will not bite them in the ass. Ask yourself: "Have I ever provided my team with a fixed-scope fixed-budget fixed-quality assignment, referring back to their initial estimate on unclear specs?". You probably have.
The other way is to remove uncertainty. If they refuse to make any assumptions, you have to make the assumptions for them. Answer every question they have, assuming either worst case, best case, or a realistic in-between. You can then communicate their estimates very clearly, because you know the assumptions behind them. Ensure broad functionality is split into smaller user stories to reduce uncertainty.
Comment: Great concise answer!
Answer: Please consider the games presented by James Grenning: http://www.renaissancesoftware.net/blog/archives/36
In particular, deal-and-slide has done me well.  These games really seem to take a lot of the time out of the exercise and make it more fun.
A lot of the trouble you're having is that the team is afraid that any number they give is a hard commitment, or will be seen that way by managers further up the chain of command. If you pull them together to get rough sizing with the intent of making estimates later, you might have more success. Of course, if a number of "size one" stories are done and all take two days, you'll have a sense of what "size one" stories are.
Answer: In essence, high-level specification can produce only high-level estimates.
Think of it from the developer's perspective. You are asking them to estimate and commit to a big unknown. It is like asking how much is to buy a nice car.
There are several approaches suggested already. Mine would be:

Try to get +/- 50% estimate, and re-estimate as you get more info about the scope. Make sure that you explain the process to the developers, because if you hard-press them for estimates they will over-estimate to protect themselves.
Use parametric estimations. How much did a similar piece of work cost, or take time? Take into account seniority of developers involved, their availability, are they spread across several projects, etc.

But, whatever approach you take, you'll have to re-estimate the project on a regular basis and all stakeholders should be aware of the approach and the situation.
Another issue here is the fact that the team is reluctant to provide any kind of estimates. It is usually because there is no trust in the team, or between the teams. Potentially it could be a huge issue and it should be addressed promptly but carefully.
Answer: Change the consequences (real or perceived) of the team over or under estimating.  It sounds like they feel they will be held to the estimate with dire consequences if they get it wrong.
If you are producing fixed price quotes for clients based on those estimates, you will get burned (particularly with only 10% - 6 months ahead you should factor in a minimum of 50% deviation). This creates a huge disincentive for the team to estimate.
Consider moving to hourly pricing, build in higher margins/reserves and improve your requirements gathering process.  All of these will change the environment in which the estimates are produced and therefore change the dynamic between the pm and the team doing the estimating.


Bounty Programs for Open Source Projects

Question: I am interested in data that contains bounties or paid rewards for specific programming tasks in open source projects.  Ideally, the data would contain a description of the task, the amount of the bounty, task status (e.g. open, in progress, complete, etc.), and a link to task homepage or public repository.  I'd also like to distinguish between bug bounty programs typically offered by private firms and platforms that price issues in public respositories (e.g. Gitcoin, IssueHunt, BountiesNetwork).  I am interested in both but I would prefer OSS bounty platforms.
Answer: I've compiled a short list of potential sources to answer the question:

https://www.freelancer.com/
https://www.bountysource.com/
https://www.bounties.network/
https://internetbugbounty.org/
https://gitcoin.co/
https://issuehunt.io/
https://whitehub.net/
https://www.boss.dev/

Any other suggestions, edits, or comments welcome.
Answer: I do not know up to which extend the spirit of the original answer by @sboysel is preserved by including the fees with a link to the source for the fees, so I posted it as a separate answer:

https://www.freelancer.com/feesandcharges?w=f&ngsw-bypass=#
max(3%,$3)

www.bountysource.com/fees
Free, but withdrawel costs 10%

https://www.bounties.network/
website not available (for me)

https://internetbugbounty.org/charter.html
Appears to be free (it is sponsored)

https://gitcoin.co/legal/terms
10 %

https://issuehunt.io/terms
10 %

https://whitehub.net/ -> https://cystack.net/en/terms
4.1: Costs are obfuscated as an unspecified function of what one has to "pay to purchase service packages"

https://www.boss.dev/policies#privacy
Obfuscated as: "a flat fee ("Flat Fee"), a percentage of the Listing price ("Commission")"


How do i know how to use the 为?

Question: I want to know how to use the 为, because there are cases where we dont translate it and it gets it harder so i'd like like to know the uses and effects this one provoke in the sentence.
Comment: You can find a grammar book. The usage of 为 is a little complicated.
Answer: I am no grammar expert, but let me attempt an answer based on my level of attainment. I am sure others could do better.
This is one of the most commonly occurring and useful word in the Chinese language, just about behind 的 & 了。
The problem is, (just like 的 & 了), it is a preposition, and when used in combination it becomes a verb, a conjunction, an interrogative, (a sentence of inquiry that asks for a reply)
So it is in an actual sentence that its usages become apparent.
As a preposition it is "for"; 他的牺牲是为了什么?, (his sacrifice is for what?)
As a conjunction it is "because of"; 他为爱国以牺牲了生命, (Because of his love for country he sacrificed his life)
As a verb -- 成为 -- "become"; 他的牺牲将会成为传说, (His sacrifice would become a legend)
As an interrogative -- 为什么, "why", 他为什么牺牲自己的生命?, (why did he sacrifice his own life?)
Answer: A good start is the Chinese Grammar Wiki page for 为, which I'll go through.  Each of the relevant webpages have multiple examples, but I'll add some in-the-field examples.
By itself, 为 basically means "for" along with some related definitions.  Perhaps the "cases where we don't translate it" arise when 为 is used within words such as 因为, 为什么, 成为, 行为, 为何, 以为, 认为, 作为, etc., where it doesn't mean "for" (it's just part of the word).
The simplest usage has the structure:

为 + Party + Verb / Adj.
Expressing "for" with "wei"

Examples:

爸妈,今天我为你包饺子![src]  (Dad and mum, today I made dumplings for you!).
我这次来上海为大家演讲[src] (This time, I come to Shanghai [to] make a speech for everyone).
为社会为世人尽力[src]  (For society, for people, strive [your] hardest)

This structure is similar to:

为了 ⋯⋯ ,Subj. ⋯⋯
Expressing purpose with "weile"

Examples:

为了您的身体健康,请少饮酒[src] (For your bodily health, please drink less alcohol.)
为了爸爸妈妈,我要努力![src] (For father and mother, I will try hard!)

It's also similar to:

Subj. + 为 + Goal + 而 + Efforts Made
  Subj. + 不 + 为 + Goal + 而 + Efforts Made
Explaining purpose with "wei... er..."

Examples:

为自己而学 (Learn for yourself [although more like "learn for your own reasons"])
为中国而战[src] (Fight for China)

There's also a song called 为爱而生 = "Live for love".
And also similar to:

⋯⋯ 是 + 为了 / 因为 ⋯⋯
Expressing purpose with "weile"

Examples:

人来到世上是为了什么?[src] (Mankind is on earth for what?)
上班不是为了赚钱[src] (Going to work is not for making money.)
成功是因为态度[src] (Success is because of attitude.)
有时候,喜欢听歌不是因为歌唱的好听[src] (Sometimes, liking to listen to a song is not because the song sounds good)

The final one is similar, but follows a specific pattern:

以 + A + 为 + B
Using "yi... wei..."

Examples:

以朋友为话题的文章[src] (An essay taking [a] friend for [the] topic)
以我家为例, ...[src] (Take my family for example, ...)

This is also used in a lot of idioms, e.g. 以黑为白 literally means something like "take black for white" implying something like "wrong is right".
Answer: There are several usages of 為, I just list part of it. Sometimes, 為 show that things are or are done for object after 為. For example, 他為我留了一塊蛋糕。 in English: He left a piece of cake for me. This example shows that thing was done for object after 為 (我). Sometimes, 為 shows that something after 為 is used to describe something before 為. 這餐花費為1000元。 in English: This meal cost for 1000 dollars. This example shows that something after 為 (1000元) is used to describe something before 為 (這餐花費). 成為傳奇。in English: Become a legend. This example show that somethings after 為(傳奇 in English: a legend) was used to describe something before 為(成 In English: the action of becoming something).

How do i know how to use the 为?


How to compile & execute C programs under Linux?

Question: I'm migrating to from Windows to Linux and I heard a lot about Linux and how you can do some real good programming under Linux. But I'm have no idea about how to compile a code written in C on Linux.
Answer: Compile your source file prog.c with:
 $ gcc prog.c

this will generate an executable named a.out. Execute it with:
 $ ./a.out

To specify the name of the executable during compilation:
 $ gcc prog.c -o prog

execute with:
 $ ./prog

gcc is also the C++ compiler. There are plenty command line options available, so it's worth getting to know the man page.
Here is the manual for the most recent version of the compiler.
Answer: Find a tutorial on the Gnu Compiler Collection and read it all trying examples on an hello world program. Make obvious errors to get used to the error messages that it spits out and look them up. There is a wealth of knowledge online about different messages. You can copy and past them into google and find good results.
A good book would be (An Introduction to GCC) by Brian Gough :ISBN 0-9541617-9-3:
One thing you should always include in compiling is the -Wall flags(the W is in caps). It tells gcc to spit out the most common error messages.
geany is the text editor I uses as it is light weight fast and includes just about anything you could need in an IDE.
After you get used to gcc check out make as they go hand in hand for projects. What make does is provide a way to compile everything with out having to remember what libs need to be manually included for linked on compile time form the terminal. It also makes you life easier and easier as a project gets more complicated.


Rhythmbox hangs when changing song properties

Question: I am having problems when trying to change song properties in rhythmbox 2.98 (Ubuntu 13.04). I just choose one song, click on properties and do some changes and press close. Now everything seems fine, but it is not. Trying to open properties one more time hangs rhythmbox - it becomes unresponsive for a long tome, but changes really occur, if I wait long enough, additionally timeout was reached error has been shown.
I think problem might be in where I have saved songs, because when I copy the song to home folder which is on the same partition as whole system, then editing goes fine.
About songs: they are saved on another ext4 partition and it is mounted on start-up by fstab. I am not sure if it is correct. fstab record here:
UUID=3265c492-8ff6-4421-830e-91508d27a020 /mnt/home ext4 auto,user,rw,sync,exec 0 2

Hope someone can help me, because I don`t know where else to go.
Thanks!
Answer: Okay, I found out what was the problem.
It was my fstab record, just changed to
UUID=3265c492-8ff6-4421-830e-91508d27a020 /mnt/home ext4 defaults,user 0 2

and now everything is fine. Problem was sync option that made that partition awfully slow, so slow, that none of the programs could work normally, also thunderbird.


Stack Exchange Structure Using Ethereum

Question: Could one build a "Stack Exchange" like information structure or process over Ethereum? Could the "Stack Exchange" team use Ethereum to build a new and improved information learning structure? As it is people could make multiple accounts(or share one account) to trick the "Stack Exchange" process just as much as they could do the same to trick the Ethereum system. But, using Ethereum fuel could someone make a "Stack Exchange" 'like' Ethereum based program to infuse true value into actions of contributing individuals?
Comment: Duplicate of https://ethereum.stackexchange.com/questions/1231/can-i-run-a-website-on-ethereum-or-only-with-ethereum
Comment: I don't think this is a duplicate. Deploying a "website" isn't the same as building something like stack exchange (rep, tags, etc.).
Comment: Did someone say Steemit.com... I may not feel that IPFS is working fast at this time, and may never... we need to find a way to get all block-chains to work together at making IPFS more robust. I am still hoping Ethereum can be the one to do this.
Answer: I see how this question maybe a duplicate, but I'll give a take on it since the question asks about "structure" instead of "site".
Ethereum is a platform for decentralized applications, with a focus on global consensus (agreement) of computation and logic.  By itself, Ethereum is not designed to be a content platform.
In terms of structuring a "StackExchange-like" DApp on Ethereum, the general recommendation is to store data on other technologies such as Swarm and or IPFS.  Hashes of the data is what would be stored on the blockchain, and the DApp would query the storage technology for the actual data, and then present it to the user.
What else could be stored on the blockchain?  The logic for voting and the votes themselves could be stored on the blochain: the purpose would be secure, transparent voting where no administrators could override the number of votes, and vote totals could only be altered according to the rules and logic encoded in the smart contracts.
Comment: I like your answer, but I can't say I currently understand enough to definitively say it correct. I also want to give anyone else a chance. This definitely a better start than I could have hoped for. My question is about the "structure" not "site", I am talking about the process not the specific hosting, everyone could equally host, though that may create security issues. I like this IPFS, thanks for that.... tell I learn more, thank you.
Comment: Yes, I hope others provide answers too and there is no rush to accept answers.  For other people that answer, you may want to clarify what you mean by "process" (it's also not that clear to me what you mean).  Thanks and welcome to the community :)
Comment: Someone shared this with me on Facebook, It does not cover the internal code based processes of stackexchage but it does show some order of the SQL, processing, and final CentOS http output(for us something like swarm, storj, maidsafe, filecoin, sia.tech). I think the data processing is easiest to manage on the Microsoft OSs(may also provide legal/liability protection of some-kind...). Cool stuff though... http://nickcraver.com/blog/2016/02/17/stack-overflow-the-architecture-2016-edition/
Answer: Storage directly on the blockchain is very expensive. Something you could do is store hashes of comments on the blockchain, along with votes, and store the comments themselves on IPFS or Swarm. It'd still be kind of expensive but might be feasible, especially once sharding is deployed.
Answer: I think it's possible to build a "Stack Exchange" like information structure or process over Ethereum https://jidex.io/currency/eth. However, I'm not sure if the "Stack Exchange" team would be interested in doing so.

Stack Exchange Structure Using Ethereum


How does gravity work underground?

Question: Would the effect of gravity on me change if I were to dig a very deep hole and stand in it? If so, how would it change? Am I more likely to be pulled downwards, or pulled towards the edges of the hole? If there would be no change, why not?
Answer: The other answers provide a first-order approximation, assuming uniform density (though Adam Zalcman's does allude to deviations from linearity).  (Summary: All the mass farther away from the center cancels out, and gravity decreases linearly with depth from 1 g at the surface to zero at the center.)
But in fact, the Earth's core is substantially more dense than the outer layers (mantle and crust), and gravity actually increases a bit as you descend, reaching a maximum at the boundary between the outer core and the lower mantle.  Within the core, it rapidly drops to zero as you approach the center, where the planet's entire mass is exerting a gravitational pull from all directions.
The Wikipedia article on "gravity of Earth" goes into the details, including this graph:

"PREM" in the figure refers to the Preliminary Reference Earth Model.
Larger versions of the graph can be seen here
And there are other, smaller, effects as well.  The Earth's rotation results in a smaller effective gravity near the equator, the equatorial bulge that results from that rotation also has a small effect, and mass concentrations have local effects.
Answer: Assuming spherically symmetric mass distribution within Earth, one can compute gravitational field inside the planet using Gauss' law for gravity. One consequence of the law  is that while computing the gravitational field at a distance r < R (with R being the radius of the Earth), one can ignore all the mass outside the radius r from the center
\begin{equation}
\oint_{S_r} g_r \cdot dA = -G \int_{B_r} \rho dV
\end{equation}
where gr is the gravitational field at distance r from Earth's center, ρ is Earth's density, Sr is the sphere of radius r centered on Earth's center of mass and Br is the volume enclosed by Sr. Assuming that ρ only depends on the distance r from the center of the Earth, we can simplify this as follows
\begin{equation}
\oint_{S_r} g_r \cdot dA = -4\pi G \int_0^r \rho(s) ~s^2ds
\end{equation}
\begin{equation}
g_r = -\frac{G}{r^2} \int_0^r \rho(s)~s^2ds
\end{equation}
Setting Mr to denote the portion of Earth's mass enclosed within Sr, we can rewrite the last formula as
\begin{equation}
g_r = -\frac{GM_r}{r^2}
\end{equation}
Now, letting ρr denote the average density of the portion of the Earth enclosed within Sr, we have
\begin{equation}
g_r = -\frac{4 \pi G \rho_r r}{3}
\end{equation}
The conclusion is that the gravity inside Earth depends roughly linearly on the distance from the center of the planet and density variations account for the deviations from linearity.
An interesting way to visualize this is to think of an over 12,700 kms long elevator from Hamilton, New Zealand to Cordoba, Spain. During the travel (which at average speed of 200km/h would take almost three days) passengers would feel gradual and roughly linear decrease in weight and in the middle of the journey would experience weightlessness followed by gradual increase in weight as they near the surface on the other side. Also, around the midpoint of the journey the floor and the ceiling would swap.
Comment: Old answer but you missed a 4$\pi$ in the first equation.
Answer: Acceleration due to gravity at depth d below the earth's surface is given by:
$g(d) = G M_e \dfrac{R_e - d}{R_e^3}$
Where,
G = Universal gravitational constant
Me = Mass of the earth
Re = Radius of the earth
d = depth below the earth's surface

Comment: Do you have a source for this?
Answer: This is a really interesting problem which have had a first solution from ancient greeks (I heard Carlo Rovelli to recount this). Indeed, when you dig a hole in the Earth, gravity starts to become proportional to distance and, if you will dig in the way to open up a hole to the other side of the Earth, a mass will oscillate in the well you created.
Comment: The ancient Greeks knew about Newtonian gravity?
Comment: While the claim about ancient people knowing roughly what would happen may seem implausible remember that Eratosthenes did a pretty good job of measuring the circumference of the earth around 194 bc.  It's very plausible that it was suspected well before that. If you can walk around the ball, it makes sense they could describe what would happen abeit with words and not an accurate equation when something was dropped through it.

How does gravity work underground?


When would you call a 7th chord first inversion a 6th chord?

Question: I read the question C major 6th chord and A minor 7th chord: same notes but different quality, why?, and it talks about the quality of the different chords. But when would you call a 7th chord first inversion a 6th chord? I'm sure there's other pairs of chords where this question could be applied also.
Answer: Context is always important when naming chords as many chords can be named multiple ways.
When given a choice between a chord like Am7/C or C6 the default is to call it a C6 for a good reason because have the bass note be perceived as the root is very typical rather than assume the chord is in first inversion.
In almost every case those two chords serve the exact same function, however it should be noted there is an obvious case where one would be preferred over the other and that is when the relationship between the chords of one makes more sense then the other.
The simplest explanation is in the case of when this chord is preceded by a dominant. If the chord before was and E7 or some variant of it, you would most likely want to the next chord as some kind of chord with the root of A to show the tonic-dominant relationship and in this case you would name it Am7/C. If the chord before was and G7 or some variant of it, you would most likely want to the next chord as some kind of chord with the root of C to show the tonic-dominant relationship and in this case you would name it C6.
Comment: Actually, the biggest determinant of function is what happens to the fifth of the chord (e.g., G in a C6). That is to say that what follows the chord is more important than what precedes it. E7 _can_ precede a C chord of some sort - that's just a deceptive progression. If the fifth of the chord resolves, you've actually got the first inversion of a minor seventh chord. An added sixth chord, however, acts like a consonance, and the fifth of the chord doesn't resolve as if it were the seventh of an inverted chord.
Comment: C6 chord could also be an added tone chord.
Answer: If you're going to call it C6, it's because it's in a sequence where C is more predominant than A, for instance, in a sequence C, C6, Cma7, C6. If it was preceded by the dom.5 of A,(E), it would then take the mantle of Am7. If it was, say, C6, 1st inversion, thus, in isolation, could be either, then the chords either side would dictate technically what it's called, leaning towards the actual key - C or Am.


transfer ebooks protected by DRM to a new device -- how?

Question: Imagine I have put some protected by DRM ebooks into a computer; imagine this computer becomes old or breaks, so that I have to change it, but I have forgot the chosen ID; how can I read these ebooks in the new computer?
Answer: It probably would help to know which company's  DRM you are talking about.
First, with Adobe ID, there are ways to retrieve the password or even the ID if you have the correct email associated with the account.
In some cases (not often, thankfully), the ebook distributor might allow you to download an ebook only once and not let you download it again. In that case you are out of luck.
In other cases, the ebook distributor is out of business, so you cannot retrieve the password or login.
This is one advantage of choosing a DRM-free distributor like smashwords (instead of apple, Adobe, Kindle). You can keep backups -- and as long as it's a well-known format, you can read it in other reading systems.
On the other hand, distributors with DRM try to keep the ebooks available in the cloud so you you can read it in on different reading systems. This of course assumes that the distributor makes reading apps for different operating systems (as do Google and Kindle, but not Apple, for example).
It's possible that there are ways to break the DRM, but discussions about these things are not appropriate here (and it may be illegal in your country).
Comment: Note that distributers don't choose if DRM or not it is the publisher - there are DRM free ebooks on Amazon and Google, Kobo etc


avoid auto-plagiarism in publishing results from PhD thesis

Question: I'm currently writting my thesis, where are exposed unpublished results that I would like to publish (may be after my PhD defense). Can I directly re-use text from my thesis ?
Answer: It would be better to cite your thesis as you would another work. You can list it in the bibliography as you would any other work, but mark it (unpublished). This is similar to citing the unpublished work of other people, and marking it as (private communication) just to make it clear.
Of course, if your thesis is in (will be in) some publicly visible repository, then clearly you should cite it there.
On the other hand, if you don't intend to publish your thesis, then the work you derive from it are original/first works and  you could, in theory, treat the thesis as a draft, in which case citation isn't really needed. But it could give the wrong impression if someone finds the thesis somewhere, such as a library repository.
Note that the reason for avoiding self plagiarism is to let a future reader visit the complete context of a work. Simply reusing, rather than citing, your own words short circuits this.
Comment: Like Buffy said.  It is fine and normal but just cite it.  It is not treated as publishing same work in two journal articles (and even that has some flexibility if you look at how some people treat conference proceedings).  In addition, same is true in reverse, you can/should publish ahead of your thesis and then cite/reuse it.
Answer: A finished thesis is a publication so any studies it includes will technically be published when you have successfully submitted your thesis. Finished theses are typically placed in university libraries and digital institutional archives and indexed in scholarly research search engines like ProQuest.
That said, there is broad recognition that theses are special kinds of publications and work is often included in a thesis despite having been published elsewhere or may be published after the thesis.
There are two major concerns:

The first is about copyright. At many universities, a thesis reflecting work does as a funded research assistant will be owned by the university. This may prevent signing a copyright agreement with a journal or publisher.
The second issue is around what you call "auto-plagiarism" and which is often called "self-plagiarism" which is a complex and controversial term used to describe attempts to inappropriately get credit for publishing the same material multiple times.

The two issues are related by distinct. Although both must be negotiated, neither will necessarily prevent you from publishing material in your thesis as an article after the thesis is done. They likely will constrain how you go about doing so.
In terms of copyright, this page by the MIT libraries about theses and copyright will give you a sense of how to negotiate the situation. It's complicated and may involve asking your university or a journal publisher for special permission.
In terms of self-plagiarism, your best bet is to be completely forthcoming at all stages. Explain in the text of your articles that the work in the article was adapted from material in your thesis. Provide a citation! Mention this fact in your coverletter to any journal.
Do research first into publishers policies in this regard before you submit. Although the large majority of publishers will publish material previously included in a thesis, there are a small number that will not. This page by the MIT libraries documents the arrangements with a couple dozen big publishers in science and engineering. Many publishers include this information on their websites and in their Frequent Asked Questions documents. Contact a librarian at your university or send an inquiry to a publisher if you have any questions.


Calculating triple integral $z^2$ over an ellipsoid

Question: I am preparing for an exam and one of the practice questions (not homework, just for my benefit) asks to simply calculate $\iiint z^2dV$ over the ellipsoid $x^2+4y^2+z^2 \leq 1$. I'm not entirely sure how to take the limits of the integration. Could someone guide me through the process?
Answer: This question uses a small trick using two changes of variables.
First do the change of variables $\tilde{y} = 2 y$. The Jacobian determinant is then $\frac12$. In other words
$$ \iiint_{x^2 + 4y^2 + z^2 \leq 1} z^2 \mathrm{d}x\mathrm{d}y\mathrm{d}z = \frac12 \iiint_{x^2 + \tilde{y}^2 + z^2 \leq 1} z^2 \mathrm{d}x \mathrm{d}\tilde{y} \mathrm{d}z $$
Next change to spherical coordinates, since you are now integrating in the sphere of radius one (with $x = r\sin\theta\cos\phi$, $y = r\sin\theta\sin\phi$ and $z = r\cos\theta$)
$$ \iiint_{x^2 + \tilde{y}^2 + z^2 \leq 1} z^2 \mathrm{d}x \mathrm{d}\tilde{y}\mathrm{d}z = \int_0^{2\pi}\int_0^\pi\int_0^1 r^2\cos^2\theta \cdot r^2\sin\theta \mathrm{d}r\mathrm{d}\theta\mathrm{d}\phi = \underbrace{\frac15}_{r} \cdot \underbrace{2\pi}_{\phi} \int_0^\pi \cos^2\theta \sin\theta \mathrm{d}\theta $$
Now
$$ \int_0^\pi \cos^2\theta \sin\theta \mathrm{d}\theta = -\left.\frac13 \cos^3\theta \right]^\pi_0 = \frac23 $$
So we get that the integral evaluates to $\frac12 \frac15 2\pi  \frac23 = \frac{2\pi}{15}$.
Answer: First, I think you are missing something small from the volume differential (try drawing a picture...I think you need $\sin(\theta)$). From the spherical coordinates I think you end up with a restriction on only one of the three parameters. This means that you don't really have restrictions for the other two (ex. just have $0$ to $\pi$ for $\phi$). Also, when you integrate over one variable, you can keep the others constant. Hope this helps. =)
Answer: When you change variables in a triple integral then your volume element is replaced as follows:
$$dxdydz\to Jdrdudv$$
where $J$ is the Jacobian determinant. For spherical coordinates
$$X\left(u,v\right)=\left(\begin{array}{c}
r\sin u\cos v\\
r\sin u\sin v\\
r\cos u
\end{array}\right)$$
Jacobian is given by the following formula $J=r^2\sin^2 u$. $r$ ranges from 0 to
$$\rho\left(u,v\right)=\frac{1}{\left(\sin^{2}u\cos^{2}v+4\sin^{2}u\sin^{2}v+\cos^{2}u\right)}$$
Hence your integral shall be expressed as follows:
$$\int_{0}^{2\pi}\int_{0}^{\pi}\int_{0}^{\rho\left(u,v\right)}r^{3}\sin u\cos^{2}udrdudv=\int_{0}^{2\pi}\int_{0}^{\pi}\frac{\sin u\cos^{2}u}{\left(\sin^{2}u\cos^{2}v+4\sin^{2}u\sin^{2}v+\cos^{2}u\right)^{2}}dudv
$$
Comment: Note that the formula in the jacobian above is wrong. It should be $r^2\sin u$, not $r^2\sin^2u$. (It cannot be edited because the change is less than the 6 characters needed by this stupid interface)


What should be the relation between margin and padding?

Question: In grid-based layouts, should there be any relation between margins (the distance between elements) and padding (the distance between an element content to its edges)?
Answer: No, there is no universal ratio or size for margin and padding. What looks harmonious in design A might be quite peculiar in design B. Off-key elements can be intentional design choices and the intention of the designer. So anything goes. That said...
The common idea is that dissonance distract. Therefore most designs require margins and paddings that go harmonious with other elements. Tips to get a harmonious margin and padding:

Read about golden ratio and Fibonacci sequence.
Look up the Canons of page construction.
Be inspired by the rhythm in and between other page elements like grid
size, page margins, column gutter, line height, etc.
Create your initial layout with gray frames in stead of actual text. This let's you isolate the design challenge, focusing on the design choices at hand. A temporary paragraph style that styles text as gray lines can be helpful.
Look at other publications.

If your logically reasoned margin and padding still feel a bit off (which is perfectly possible because all elements influence each other), than you can create ranges of variations, adjusting a single parameter at the time. Pick the variation that looks right. Saving your variations allows to look back and reflect on the design choices you made. Iterate over all parameters as long as you're not satisfied. In the beginning you can use bigger steps and exaggerate, narrowing down to almost not noticeable fine tuning.
Answer: No, this is quite dependent on what you're trying to accomplish.
Personally I try to remain with a minimum of 5px padding and 10px margin. But again its down to how you want the page to look.
Sometimes padding will do the job of the margin if the background-color is to touch the neighboring element..
..where-as the margin would push the two background-colors apart.
So this would be again down to how you want the style of the page, in some cases this maybe stricter than others.
Answer: No - If it LOOKS right, it IS right.
You are the designer, rules are there to be broken :-)
If nobody played about, everything would look the same.
Comment: Subjective? I disagree with that statement. The choice to use padding or margin is absolutely _objective_ based on what you are trying to achieve
Comment: I don't think this advice is very solid, margin and padding have different functionality and shouldn't be arbitrarily chosen based on looks
Comment: its entirely subjective, based on what you are trying to acheive.
Comment: So what you are saying is, even if it looks right, it might be "wrong"...
Comment: Some rules can't be broken. Like you can't make an image go off-canvas on the right without a horizontal scrollbar. It's the rule of HTML.


What is the difference between machine learning and deep learning?

Question: Can someone explain to me the difference between machine learning and deep learning? Is it possible to learn deep learning without knowing machine learning?
Comment: The difference is that deep learning includes implicitly representation learning in their models.
Answer: Deep learning is a specific variety of a specific type of machine learning. So it's possible to learn about deep learning without learning all of machine learning, but it requires learning some machine learning (because it is some machine learning).
Machine learning refers to any technique that focuses on teaching the machine how it can learn statistical parameters from a large amount of training data. One particular type of machine learning is artificial neural networks, which learn a network of nonlinear transformations that can approximate very complicated functions of wide arrays of input variables. Recent advances in artificial neural networks have to do with how to train deep neural networks, which have more layers than normal and also special structure to deal with the challenges of learning more layers.
Answer: Deep learning is one form of machine learning.
Deep learning refers to learning with deep neural networks, essentially networks with many layers.
Neural networks are one group of many forms of machine learning:

Neural Networks
Decision Trees and Random Forests
Support Vector Machines
Bayesian Approaches
k-nearest neighbors
Answer: First, in most condition machine learning actually refers traditional/classical machine learning, and deep learning is specifically referring multi-layered neural network, and neural network is one of the machine learning approach.
Second, Machine learning especially supervised machine learning requires engineers to design and predefine features manually, which are used to represent the data in numerical way. Such as we can represent animals with three features such as the number of eyes, the number of legs and the number of heads. The data [2,4,1] representing an animal with 2 eyes, 4 legs and 1 head. In this scenario, the feature is extracted by us, because we have knowledge on animals, and we think these features can represent animals.  However, instead of hand-crafting features the deep learning learn the features automatically.
Third, when someone say machine learning he is saying algorithm, such as naive bayes, decision tree, linear regression etc. However, the deep learning is more related to the framework and architecture such as RNN, CNN, Transformer etc.
Fourth, it is possible to start deep learning without knowing machine learning, sources from internet like Andrew Ng's course usually covers most topic you should know in deep learing. Try search Andrew Ng, I think he is really good!
Comment: This is a good answer that emphasizes that in traditional ML approaches we usually need some form of "feature engineering" (which is a term that you may add to your answer). However, note that when we say deep learning we are not just referring to the architecture but also the algorithms, in particular, gradient descent and back-propagation, which are typically the algorithms used. See also [this answer](https://ai.stackexchange.com/a/22725/2444).
Answer: When I started Machine Leraning chapters in book used to look like this

I) Supervised:

Regression

Linear models

Classification

Logestic Regression
Neural Network
Decision Tress and Random Forest
Boosting and Bagging
SVD and SVM

II) UnSupervised Learning:

Clustering

K-Means
Hierarchical
Gaussian Mixture Model
DB Scan

Association Learning.

III) ReInforment Learning:

All of a sudden chapter I>2>b created a sub-field of its own . Well to know why, let me tell you a bit of history. Machine learning word was coined in 1959 by Arthur Samuel to signify that machines were able to learn from data than explicit instruction. Initally it was broken into two groups based on if th approach required label data or not(ie regression, classification), then they realised we can cassify by clustering too which gave birth to unsupervised. And word reinforment learning was born inspired by areas of game theory. Lets keep those details aside for later.
Coming to deep learnign, the word deep learning came very recently, as recent as 2008 from a Geoff Hinton conference. There people started using it to indicate a very deep neural network architecture used in a paper presented by Geoff Hinton and from then onwards it kind of became as a new way of classifying machine learning besides supervised, unsupervised or reinforcement.(Disc: There may be odd reference of calling NN as DL before this but not so popular and acceptable prior to this)
Well I sometimes feel the name deep learning is somewhat misnomer, it would have been better of if it was named as neural learning or to stress on depth maybe deep neural learning. If you are new you might be wondering what depth I am talking about, the entire word deep came from the fact that neural network (thanks the availability of high processing abilities of GPUs) were now able to train successfully on multiple layers. The word deep can also be loosely used to include other non-neural network areas of machine learning which requires lots of computation like deep belief net or recurrent net. To be precise the units of the networks today are no longer a mere neuron or a perceptron, it can be LSTM, GRU or a capsule, so I guess word deep now makes more sense than before.
Answer: Deep Learning is subset of Machine Learning.
Machine learning and Deep learning both are not two different things. Deep learning is one of the form of machine learning.
The level of layers in Neural network are more and more in depth learning is part of Deep learning.

"Deep learning is a particular kind of machine learning that achieves
  great power and flexibility by learning to represent the world as
  nested hierarchy of concepts, with each concept defined in relation to
  simpler concepts, and more abstract representations computed in terms
  of less abstract ones."


What do I say to make a new line when using voice recognition?

Question: I've found I can make punctuation happen by saying "comma", or "period", but I can't find the word for new line.  I tried "paragraph", and "line break", but it just prints those words.
Answer: I found that saying period newline gives you a new line, after putting a period on the current line.
Also period new paragraph work.
Comment: I've upgraded to Android 4.3 since I asked this question, and this answer seems correct.  `period newline` and `period new paragraph` both work.
Comment: Things must have changed again, because none of these suggestions work anymore.
Comment: I can confirm this works on Moto X running Android 4.4.2.
Comment: I am running Moto-X and for me "Full stop, new line" works.
Answer: In Android 4.0, say "New Paragraph"
Answer: For Android 4.1.1, I just say "Enter" and it will start a new line.
Answer: I said "newline" really fast and it did it on Jelly Bean 4.1.  When I said "new line" slower it filled in the words "new line."  I guess you just say it quick.
Answer: Yes, "period newline" & "newline" works, but timing is everything in this.
Ex: How to get 3 carriage returns (2 more below the end of your line): At the last word in your sentence, either say "period newline" or pause and say "new line".
Then for each additional carriage return/line feed you want, as soon as you see the blinking line move to the next line, say "newline" and it will give you another, and so forth.
Comment: A lot of the comments in this question helped the light go off, but this was a big one for me. I found that "period new line" works right away, but sometimes I am making a brief sentence fragment of a note, so I don't say period. In that case, I have to wait one second before saying "new line."
Answer: I use ColorNote to make a grocery list.  If you say for example "bacon new line", then that will be printed on whatever line the cursor is on, i.e. "bacon new line".  The cursor will not go to the new line.
But, if you say "new line bacon", the cursor moves to a new line and puts the word "bacon" on that new line.  Now, if you say "new line sugar", the cursor will go to the next line and place the word "sugar" on that line.
You have to first say "new line" and then immediately say what you want on that line.
In fact, if you say "new line newline", the cursor will advance two lines, "new line new line newline", the cursor advances 3 lines.
So, know what you want to put on the next line, and start saying it immediately after you say "new line".
Just saying "new line" without any more words will not advance to the next line.  In fact, it will print the words "new line" at the current cursor position.  You must say whatever you want to appear on the new line immediately after saying "new line". Then it works every time.  Found this out by trial and error experimenting.
Answer: short answer: "Next"
long (and more reliable) answer:

Select G-Board as your keyboard device
touch the microphone icon
After the touch, you can see a circled question mark at the far left of the screen at the same line of the microphone icon, touch the circled question mark.
It shows a help page and lists all voice commands, such as "Send", "Stop", ... etc.   The command to "enter" the next line is "Next", according to the help page.
Answer: Say, "period new line" in Android 4.4.2.
Answer: Saying "period newline". This works on my Samsung 10.
So when you are done with your sentence and you want to end it with a "period" and have the cursor move to a new line, make sure you say.
As you can see by the formatting of my last sentence, it put a period and brought me to a new line.
Comment: So you are saying you "dictated" this answer, and that "period newline" are the keywords for the action? Why didn't that trigger on your very first line yielding "Saying." only? Is there a time trigger too, so it has to be said quickly together?
Comment: There is no time limit to say it, other than how long your speech to text button turns off, if you don't speak. Yes, you are correct when you asked if I,  "dictated" this answer, and that "period newline" are the keywords for the action? The reason why it didn't trigger on my very first line yielding "Saying" is because I chose not to use that command, because that's the way I wanted to structure my answer. I hope this helps answer your questions and if I misunderstood anything let me know and I will try and clarify for you.
Answer: With Android 12 + Google Pixel 6 + Gboard voice typing: the voice command is "New line".
Answer: Without any punctuation at the end of what I say, I can just pause and say
"New line" and my Droid X goes to the next line.


HTTP Downloader Spam Answers

Question: Just a heads up to reviewers tonight: there's a newbie who has been posting answers to questions about large downloads. He has answered at least 5 other questions the same way: promoting his app. Here's a sample of his answer.
Comment: A regular spam flag on each post will get them into the general review queue, and other users will make short work of them. Adding a comment makes it easy for other users to see what's going on, and look for the other posts. A serial spammer is a separate issue, since you want a mod to take action with the user, independent of the posts. A custom flag will work for that, although those are seen only by mods, so that can delay getting rid of the posts. Another way is to use regular spam flags for the posts, and for the user, either one custom flag or post a comment on the Ask a Moderator chat.
Comment: BTW, for fastest action, include a link to the user and/or posts if you raise the issue in chat or here.
Comment: @fixer1234 I would've put a link, but I was on my phone. They're gone now, thankfully.
Comment: He is up again https://android.stackexchange.com/a/206186/103727
Answer: I think there's nothing left to do at this point. It has been flagged to oblivion.
Amusingly even if it wasn't spam, IIRC google take out files are only available for a limited amount of time, I don't think you can split them...
so... it would not have been that useful anyway.
In future though. On the books? Spam flag it. Reporting it to the smoke detector team would be useful too. More or less, keep calm, and quietly call for support fire ;)
Answer: That's why Moderator is around and there is an option:

in need of moderator intervention
  A problem not listed above that requires action by a moderator. Be specific and detailed!

Just raise flag with clear message. Why you think it's need moderator attention and move on. Moderator effectively handle that.
Comment: The key words in that option are **not listed above**. Spam is the first option on the list, and flagging the answers as spam will help get them taken care of more quickly.
Comment: Flagging for moderator attention would allow this spam to exist for longer and doesn't result in an automatic downvote.  This means while the answer might eventually be deleted, if it isn't downvotes, the author is able to continue to submit spam.
Comment: @duskwuff, if the answer is relevant but intrusive, you can't be sure it's spam. As I see on the screenshot, there is not just a link, but also information about how it solves a problem. Maybe comment to the author would be enogh for him to stop posting suh answers. Also in such case flag for moderator attention is more relevant that for spam.

HTTP Downloader Spam Answers


P2P lending in Maryland?

Question: I'm interested in investment through Prosper or Lending Club, but both are not available in Maryland where I live.
Is there any other alternative that I can invest quite safely?
Comment: Having lost a decent chunk of money with Prosper, I will note that it is *not* investing "quite safely."
Comment: As an alternative to Prosper and Lending Club, I would advise withdrawing your funds in small bills, which you then set on fire. This will generate a predictable amount of heat.
Comment: Sounds like sour grapes.  Of course p2p is speculative, the precise opposite of safe.  But people who do their homework and diversify have made good money - look at http://money.stackexchange.com/questions/4830/peer-to-peer-lending-sites-good-investment-or-insane, or http://whitecoatinvestor.com/tag/p2p-lending/.
Answer: Peter Renton's Lend Academy blog is a great resource for those interested in P2P lending, but it gives a somewhat misleading impression for why investing is available in some states and not others:

Apparently even though p2p lending is regulated by the SEC, it is
  still up to the states to decide if they want to allow this kind of
  investment.

I recently asked Maryland's Office of the Attorney General why P2P lending was not allowed here, and received this surprising response:

There is no provision that prohibits peer to peer lending ("P2P").
  Such lending companies are permitted to operate in Maryland in
  compliance with the State's securities registration requirements.  Two
  companies, Prosper Marketplace, Inc. and LendingClub Corporation,
  filed to become registered but, in May 2010 and March 2010,
  respectively, these companies abandoned their filings in Maryland and
  chose not to pursue registration.
Since that time, Prosper Funding, LLC, and later both Prosper Funding,
  LLC and Prosper Marketplace, Inc., as co-issuers, have filed a
  registration application in Maryland; the status of that application
  is the companies have asked for additional time to respond to the
  Division's questions.
Any company that wants to conduct P2P lending may do so provided the
  company does so in compliance with Maryland law.  The timetable for
  those companies to become registered is up to them, but won't happen
  unless they file and pursue their applications for registration.

I've asked Lending Club whether they intend to ever register in Maryland and have not yet received a response.  But it appears that Prosper is at least working on registration.
Answer: Crowd funding could be a good option. But how viable it is for your needs, I cannot comment on it. A google for crowd funding gave me a number of websites, but I believe you have to figure out which one is best for your needs and available in your state.
Answer: Can you buy notes from secondary transaction platform foliofn? I am not sure if MD allows using secondary platform transaction. If you are really interested, you can collaborate with some acquaintance in states that permit p2p notes and purchase notes through foliofn from them. It will cost you additional 1% but in my opinion worth the opportunity.

P2P lending in Maryland?