Q: Meaning of downvotes in Meta vs Main sites? Upvotes are easy on both Main and Meta sites. You like something, you vote it up.
Downvotes are trickier. 
On Main down-voting a question means that the question is a poor one. Poor meaning badly written or really annoying for some reason (e.g. give-me-da-codez).
Downvoting an answer usually means it's plain wrong.
On Meta, however, many questions revolve around matters of taste (e.g. the HW question). When voting on answers to such questions, I want to be able to push down the suggestions that I disagree with and promote the ones that I think are correct. But I don't want to hurt people's reputation by doing so. 
Downvoting on Meta isn't really saying "your answer is stupid and wrong"; it's more like "I prefer we do it the other way". The whole site is basically meant to discuss matters of social preference, etiquette, do's and dont's, etc.
In Main most people wouldn't downvote an answer just because some other answer is better. People generally accept that there may be different solutions to a problem and feel comfortable in letting upvotes alone decide on the most popular one.
In Meta, on the other hand, there might be groups that really care about some issue and would like to see it solved in a particular way. And, in case meta replaces UV, voting on answers would really be voting on preference more than correctness. 
Should downvote semantics on Meta be different than on Main? 
Perhaps the system should not deduct reputation points if your answer gets downvoted, thereby allowing/encouraging more free downvoting.

A: In August 2013, the Help Center has been changed to show the following official statement:

Like normal Stack Exchange sites, Meta allows members to vote on questions and answers. For most posts, votes reflect the perceived usefulness: well-written, well-reasoned, well-researched posts tend to get more attention and more upvotes. Highly-voted and frequently-linked posts may become part of the community-curated FAQ or codified as part of the site's Help pages.
Unlike normal Stack Exchange sites, Meta invites the community to discuss, debate and propose changes to the way the community itself behaves, as well as how the software itself works. On posts tagged feature-request, voting indicates agreement or disagreement with the proposed change rather than just the quality or usefulness of the post itself.

(This does not cover voting on answers.)

A: I think downvotes on meta are just saying that you do not agree. But that can turn into people downvoting a lot.
Since opinions cant be wrong, just misinformed.
I think we should go easy on the downvotes to start with.


*

*Spam

*Offensive answers

*etc


Should be things we obviously flag (or downvote if we feel so)
I think the answer is to turn off downvotes and make the flagging feature better fleshed out.
Like sorting flagged items lower than non flagged items and showing visually if the item is flagged.

A: Now that Meta Stack Exchange is the only Meta site that maintains a separate reputation, I thought that this question should be revisited.
The problem with Meta-rep is this: while reputation doesn't mean the same thing on a regular site as MSE, it still affects what you can do on the site. Downvotes take reputation and upvotes give it. But reputation is still how you get privileges. And that's a problem.
At this moment, I've got about 970 MSE rep. If I post a number of suggestions that I see as perfectly valid, but the people on MSE don't want to see adopted, I lose a lot of rep. It's not necessarily that the ideas are bad; all it would take is that they were not… accepted among the community. And thus, simply by adding ideas to the site, I'm pushed farther away from greater privileges.
Indeed, there have been some MSE conversations that I've been reluctant to even consider bringing up, in part for these reasons. Questions about what forums are, what SE is, whether forums still have a place in a post-SE world, how best SE-style sites should build a community, the nature of a SE-based community vs. a forum, etc. My views on these issues would certainly be … controversial and in some ways antithetical to the prevailing wind of the people on MSE.
So if I were to talk about them, I lose rep. Not because I'm right or wrong, but simply because of the general feelings of the collective of people on MSE.
And that would be fine… if rep didn't give me abilities. The ability to create tags, to cast close votes, to see the up/down votes on a question/answer, unreviewed edits, etc.
For regular SE sites, reputation is a relative measure of the actual worth of the person. A person who has high rep has contributed significantly to the site. And thus, this person is more deserving of powers over the site. On MSE, this is not the case.
So my suggestion is this: leave the rep the same, but make MSE privileges based on the privileges you have for the highest rep site on your account. Since MSE is effectively shared (it's the default discussion place for Stack Exchange), it makes sense that being a member in good standing for any Stack Exchange site would transfer over. So if you are a 10,000 rep user of Super User, you would have the same privileges on MSE.

A: There's a lot of confusion here and I think it is going to be hard to enforce consistent behavior, especially because people are now downvoting the question if they don't like it. 
The Help center sentence On posts tagged feature-request, voting indicates agreement or disagreement (quoted in Arjan's answer) contributes to the confusion because it suggests you should only downvote the question if that applies. We would have to look at the tags before downvoting the question.
The confusion is totally unneccesary if we adopt this behaviour:


*

*A question should only be downvoted if is is spam, offensive, very badly written etc. Like we do on all sites.

*If you disagree with the contents/idea/suggestion write an answer why. Then people can upvote the answer to signal disagreement.

*Upvote an answer if you think it is worth asking.
With that change, the help text sentence can be dropped too.
Note that I have not been talking about reputation until now: I don't care. I only want the confusion gone.

A: The route most people will come to Meta is:


*

*Use Stack Overflow (or other stack exchange site) for a period of time, see good questions and answers voted up and bad ones voted down. 

*Notice a bug or feature they think would be good.

*Go to meta.

*(Possibly research whether it's
been suggested before)

*Post a feature request (possible that they've carefully researched and worded carefully).


I came down this route and at this point expected some or all of the following


*

*Disagreement

*Agreement

*To be ignored


However what I got (admittedly in addition to disagreement) was being downvoted to oblivion, I reworded and reworded my question, trying to make it clear and polite but the downvotes continued. Someone eventually pointed out that votes are different on meta, but a first impression sticks and that first impression was that "Meta is deeply deeply unfriendly."
The meta FAQ does mention that votes are different. But I doubt it will occure to most people that Meta and stackoverflow have different FAQs.
The section in which I whine about how people were mean to me has now ended, now I attempt to suggest some solutions:


*

*Separate out votes for/against a feature request from the normal vote up/vote down. [This probably requires much more developmental effort than I imagine and is probably not worth it]

*In meta down votes don't lead to a negative reputation, this would make downvotes feel less like you've done something wrong. [But this then causes the problem of what about questions that are poorly researched or stupid]

*Encourage a cultural change in which if you disagree with a suggestion (that is none the less well written and researched) you upvote one of the disagreeing answers (or make one yourself if there isn't one). [Clearly people are free to vote as they see fit but at present the FAQs actively encourages downvoting things you disagree with].


P.S. Is this a meta meta question?

A: Down-vote on meta == i don't like your avatar...

Should down-vote semantics on Meta be different than on SO? 

Naw. As with SO, reputation is influenced much more by up-votes than down-votes. You're gonna need to be desperately unpopular to really be hurt by 'em.

A: I view rep here as different. It means nothing about you, your trust, or your knowledge. But I'm not sure what it does mean.
I vote up a "question" when I think it raises a good, valid point or suggestion. I vote up an "answer" when I think it provides a good solution to the "question". I vote down when I don't think it's a good idea or it's a subpar solution. If I don't vote, I don't have an opinion (I don't care, it doesn't matter to me, I'm not sold yet).

A: Why isn't it enough promoting the suggestions you like? If the others stay on a low level, it is shown what the majority thinks without downvoting. If they rise also, you have to live with that.

A: Reputation in this site means pretty close to nothing.
If you disagree, downvote, preferably with a comment, and if you agree, upvote. It's not really a big deal as far as reputation goes the loss of 2 points.

A: On meta a downvote means "I'm jealous because you're right"
