user254: So how can we comment, and should we even comment, and how much shall we comment -- to question or to clarify something in an answer?
The Help topic includes a section titled When should I comment? which says ...

You should submit a comment if you want to:

Request clarification from the author;
Leave constructive criticism that guides the author in improving the post;
Add relevant but minor or transient information to a post (e.g. a link to a related question, or an alert to the author that the question has been updated).


... plus another titled When shouldn't I comment?
But beyond that:

Are there any site-specific conventions on this site about commenting?
Are there ways to post a comment without that seeming like an argument?
What can I do if I see a comment which seems out of place?


user43: This is a reasonable summary of the comment-related standards,  approaches and moderation strategies we have developed over years here at Buddhism Q&A. Nothing major seems missing or contradicting my experience.

user254: Why even comment?
A benefit of posting and reading answers on a public site, is that several users read or review each answer. Users can "vote" an answer, but a comment can be more specific or detailed, informative.
If you do read something which seems misleading or which you don't understand, in an answer, then you can post a comment. Commenting is optional (not required). If you post a comment under the answer:

The author can correct or clarify the answer, and/or reply with a comment of their own
Anyone else who reads the answer can see the comment[s] too

How to comment, and how often, how much?
Comments:

Should be polite, occasional, and relatively rare
Must be about the answer, and specific or constructive or prescriptive, for example:


"I didn't understand what you meant when you wrote X?"
"Why did you write X? Would you add a reference to what that's based on?"
"When you wrote X isn't that contradicted by scripture Y?"

Must not attack the author ("focus on the content, not the person"), so not for example:


"You are wrong"


I recommend:

When you comment, try to be clear and say everything you need to say in that first comment.
If the author replies to your comment with another comment, then think twice before replying to that -- instead try to let the answer's author have the last word, don't turn it into an argument.
If the author doesn't accept your comment, you already had your say (by posting that first comment), and other readers can see your comment -- maybe that's enough
If you want it to be a different answer, then maybe write a different answer yourself
Generally (perhaps almost always) phrase a comment as a question (examples above)
Try to clarify the answer -- i.e. what it's saying, and why and how -- more than contradicting it.

Some users only want to post their own answers, and not get into commenting. You may comment if you feel you should, but try to not disturb other users.
Are these suggestions necessary?
Maybe not!

In practice the majority of people's comments don't seem out of place -- and don't need moderating -- "polite, occasional, and on-topic" is enough of a guideline.
Off-topic comments might be distracting for readers, so do avoid those.
A little conversation sometimes is probably fine, if it seems friendly and topical --
so comments beyond what's suggested may be OK (or maybe moved to chat).

These conventions were meant to identify what form of comment is almost definitely OK -- and hopefully considered "cooperative" or "valuable" rather than "argumentative".
What if I see an unwelcome comment?
Sometimes you may see a comment which seems out of place.
Stack Exchange's strict "Question and Answer" format -- "no chat"! -- does tend to keep users from interacting or arguing. So comments, can become a cause or almost the only vehicle for arguments, and troublesome.

You can flag any comments or answers for moderator attention -- as described here (also here).
Only moderators can see flags -- flagging is confidential, your identity isn't published -- ideally you or any user can flag a comment, without creating any added hostility.
Try setting a moderator flag for any "hostile" posts, or for anything "off-topic".
But don't flag an answer for being "wrong" -- which is for the reader to assess, not a moderator -- then instead of "flagging" you can comment, and/or downvote, and/or post an answer of your own.

Guidelines for the moderators
The site's moderation policy for comments is more-or-less as described here.

The author of an answer (or any other user) may flag a comment as "no longer needed" -- but a moderator may decline the flag, and keep the comment if they think it is still helpful
The author of an answer must not delete-and-repost their answer in order to delete the comments under the first answer -- edit the answer but let moderators decide which comments should be deleted
A moderator may and/or should delete a comment they consider rude or hostile or "ad hominem" (i.e. which criticises the author not the answer)
A moderator may move comments to chat especially if there are several of them -- and should prefer to move harmless (e.g. friendly but off-topic) comments to chat instead of deleting them

Moderators are users too (or some users are also moderators). If a moderator posts a question as comment to an answer, they are probably acting as a user, commenting like any other user might.
More details
There are other 'faq' topics about comments --
on meta.stackexchange.com --
with details including how SE intended comments to be used, when to use @Username in a comment, etc.
Other discussions about comments on this site
The following meta-topics are related -- I think this (above) is a summary of the actual current ("de facto") policy and compatible with all these previous meta-topics on the subject.

Should we upvote answers more often, and/or comment more?
Some thoughts on the direction of Buddhism.SE
Posting comments to answers
What comments to take into account?
Post comments to help improve answers?
Are these comments inappropriate debate or reasonable questions?
What are comments underneath answers for?
Can you keep "you" out of hostile comments?
Unnecessary arguing


254: <p>So <em>how</em> can we comment, and <em>should</em> we even comment, and <em>how much</em> shall we comment -- to question or to clarify something in an answer?</p>
<p>The <a href="https://buddhism.stackexchange.com/help/privileges/comment">Help topic</a> includes a section titled <strong>When should I comment?</strong> which says ...</p>
<blockquote>
<p>You should submit a comment if you want to:</p>
<ul>
<li>Request <strong>clarification</strong> from the author;</li>
<li>Leave <strong>constructive criticism</strong> that guides the author in improving the post;</li>
<li>Add relevant but <strong>minor or transient information</strong> to a post (e.g. a link to a related question, or an alert to the author that the question has been updated).</li>
</ul>
</blockquote>
<p>... plus another titled <strong>When <em>shouldn't</em> I comment?</strong></p>
<p>But beyond that:</p>
<ul>
<li>Are there any site-specific conventions on this site about commenting?</li>
<li>Are there ways to post a comment without that seeming like an argument?</li>
<li>What can I do if I see a comment which seems out of place?</li>
</ul>
 43: <p>This is a reasonable summary of the comment-related standards,  approaches and moderation strategies we have developed over years here at Buddhism Q&amp;A. Nothing major seems missing or contradicting my experience.</p>
 254: <h2>Why even comment?</h2>

<p>A benefit of posting and reading answers on a public site, is that several users read or review each answer. Users can "vote" an answer, but a comment can be more specific or detailed, informative.</p>

<p>If you do read something which seems misleading or which you don't understand, in an answer, then you can post a comment. Commenting is optional (not required). If you post a comment under the answer:</p>

<ul>
<li>The author can correct or clarify the answer, and/or reply with a comment of their own</li>
<li>Anyone else who reads the answer can see the comment[s] too</li>
</ul>

<h2>How to comment, and how often, how much?</h2>

<p>Comments:</p>

<ul>
<li>Should be polite, occasional, and relatively rare</li>
<li>Must be about the answer, and specific or constructive or prescriptive, for example:

<ul>
<li>"I didn't understand what you meant when you wrote X?"</li>
<li>"Why did you write X? Would you add a reference to what that's based on?"</li>
<li>"When you wrote X isn't that contradicted by scripture Y?"</li>
</ul></li>
<li>Must not attack the author ("focus on the content, not the person"), so not for example:

<ul>
<li>"You are wrong"</li>
</ul></li>
</ul>

<p>I recommend:</p>

<ul>
<li>When you comment, try to be clear and say everything you need to say in that first comment.</li>
<li><p>If the author replies to your comment with another comment, then think twice before replying to that -- instead try to let the answer's author have the last word, don't turn it into an argument.</p>

<p>If the author doesn't accept your comment, you already had your say (by posting that first comment), and other readers can see your comment -- maybe that's enough</p></li>
<li>If you want it to be a different answer, then maybe write a different answer yourself</li>
<li><p>Generally (perhaps almost always) phrase a comment as a question (examples above)</p>

<p>Try to clarify the answer -- i.e. what it's saying, and why and how -- more than contradicting it.</p></li>
</ul>

<p>Some users only want to post their own answers, and not get into commenting. You may comment if you feel you should, but try to not disturb other users.</p>

<h2>Are these suggestions necessary?</h2>

<p>Maybe not!</p>

<ul>
<li>In practice the majority of people's comments don't seem out of place -- and don't need moderating -- "polite, occasional, and on-topic" is enough of a guideline.</li>
<li>Off-topic comments might be distracting for readers, so do avoid those.</li>
<li>A little conversation sometimes is probably fine, if it seems friendly and topical --
so comments <em>beyond</em> what's suggested may be OK (or maybe moved to chat).</li>
</ul>

<p>These conventions were meant to identify what <em>form</em> of comment is almost <em>definitely</em> OK -- and hopefully considered "cooperative" or "valuable" rather than "argumentative".</p>

<h2>What if I see an unwelcome comment?</h2>

<p>Sometimes you may see a comment which seems out of place.</p>

<p>Stack Exchange's strict <a href="https://buddhism.stackexchange.com/tour">"Question and Answer" format</a> -- "no chat"! -- does tend to keep users from interacting or arguing. So comments, can become a cause or almost the only vehicle for arguments, and troublesome.</p>

<ul>
<li>You can flag any comments or answers for moderator attention -- <a href="https://buddhism.stackexchange.com/help/privileges/flag-posts">as described here</a> (also <a href="https://buddhism.stackexchange.com/help/declined-flags">here</a>).</li>
<li>Only moderators can see flags -- flagging is confidential, your identity isn't published -- ideally you or any user can flag a comment, without creating any added hostility.</li>
<li>Try setting a moderator flag for any "hostile" posts, or for anything "off-topic".</li>
<li>But don't flag an answer for being "wrong" -- which is for the reader to assess, not a moderator -- then instead of "flagging" you can comment, and/or downvote, and/or post an answer of your own.</li>
</ul>

<h2>Guidelines for the moderators</h2>

<p>The site's moderation policy for comments is more-or-less as described here.</p>

<ul>
<li>The author of an answer (or any other user) <em>may</em> flag a comment as "no longer needed" -- but a moderator may decline the flag, and keep the comment if they think it is still helpful</li>
<li>The author of an answer <em>must not</em> delete-and-repost their answer in order to delete the comments under the first answer -- edit the answer but let moderators decide which comments should be deleted</li>
<li>A moderator <em>may</em> and/or <em>should</em> delete a comment they consider rude or hostile or "<em>ad hominem</em>" (i.e. which criticises the author not the answer)</li>
<li>A moderator may move comments to chat especially if there are several of them -- and should prefer to move harmless (e.g. friendly but off-topic) comments to chat instead of deleting them</li>
</ul>

<p>Moderators are users too (or some users are also moderators). If a moderator posts a question as comment to an answer, they are probably acting as a user, commenting like any other user might.</p>

<h2>More details</h2>

<p>There are other <a href="https://meta.stackexchange.com/questions/tagged/comments+faq">'faq' topics about comments</a> --
on <code>meta.stackexchange.com</code> --
with details including how SE intended comments to be used, when to use <code>@Username</code> in a comment, etc.</p>

<h2>Other discussions about comments on this site</h2>

<p>The following meta-topics are related -- I think this (above) is a summary of the actual current ("<em>de facto</em>") policy and compatible with all these previous meta-topics on the subject.</p>

<ul>
<li><a href="https://buddhism.meta.stackexchange.com/q/359/254">Should we upvote answers more often, and/or comment more?</a></li>
<li><a href="https://buddhism.meta.stackexchange.com/q/1711/254">Some thoughts on the direction of Buddhism.SE</a></li>
<li><a href="https://buddhism.meta.stackexchange.com/q/1793/254">Posting comments to answers</a></li>
<li><a href="https://buddhism.meta.stackexchange.com/q/1846/254">What comments to take into account?</a></li>
<li><a href="https://buddhism.meta.stackexchange.com/q/2070/254">Post comments to help improve answers?</a></li>
<li><a href="https://buddhism.meta.stackexchange.com/q/2145/254">Are these comments inappropriate debate or reasonable questions?</a></li>
<li><a href="https://buddhism.meta.stackexchange.com/q/2239/254">What are comments underneath answers for?</a></li>
<li><a href="https://buddhism.meta.stackexchange.com/q/2241/254">Can you keep &quot;you&quot; out of hostile comments?</a></li>
<li><a href="https://buddhism.meta.stackexchange.com/q/2402/254">Unnecessary arguing</a></li>
</ul>
