Commenting is one of the unsung heroes of Stack Exchange. The help center suggestions that 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).

These are all essential for coordinating the creation of useful questions and answers, but originally comments were not part of the design for this system! During the beta period, it was observed that, without a way to annotate or discuss specific posts, answers became noisy and tangential. Therefore, a separate space was carved out for this purpose below each post, leaving answers free for content that, y'know, actually tries to answer the question.

This created a problem, however: how do we expose useful comments inline with answers without adding back the same amount of noise comments were created to alleviate? The solution was to pick off the 5 comments deemed most-useful by the voters. This simple strategy proved to be quite durable, working admirably in most common cases - but it suffers from a few drawbacks:

  • Comments can become obsolete, addressing issues or concerns long ago addressed via edits to the post itself.
  • Those one-liner contests Jeff alluded to don't always produce results as charming and witty as one might like.
  • With the addition of comment replies and real-time notifications, comments can be used for casual conversation and debate - fun and perhaps even enlightening for those involved, noise for those just looking for an answer.

Thus the need for comment moderation. This involves three groups of people:

  1. The authors of the comments themselves can clean up after they're done, if they so desire.
  2. Privileged users can flag comments in response to the issues noted above, bringing them to the attention of the moderators. (They can also vote on comments, controlling to a degree which ones are shown)
  3. Moderators can remove individual comments or entire comment threads, move comments to chat, and even lock posts if comments are getting unruly.

This raises several questions, which I'll try to address below:

  1. When should I delete my own comment?
  2. When should I flag a comment?
  3. When should moderators delete comments?
  4. When should moderators move comments to chat?
  5. When should moderators edit comments?

These guidelines are based on the authors' experience moderating comments on various sites. Individual communities, particularly on meta sites, may benefit from additional guidelines - this guide is intended as a baseline.

  • In revisions page how do you comment (ask for clarification) to a modification done by another user on my post?
    – Gabe
    Commented Jan 20 at 3:45
  • You'd use comments on the post itself, @gabe
    – Shog9
    Commented Jan 20 at 18:39

5 Answers 5


When should I flag a comment?

When it will be shown to future readers but offers them nothing of value, or what value it has is overshadowed by the comment being unfriendly or outright rude.

There are many different sorts of comments that qualify here, roughly categorized by the flagging dialogue itself:

Comment flagging dialogue. "Why are you flagging this comment?" Contents described below.

The first two flags address similar behavior issues, in different degrees:

  • It contains harassment, bigotry, or abuse.
    This comment attacks a person or group. Learn more in our Code of Conduct. Abuse also covers complete, meaningless gibberish from new users who have no other positive contributions (see the FAQ on spam and abuse flags on posts). Comments which qualify for flagging as "abuse of the system" would primarily be found on posts which also qualify for flagging as abuse for the same reason, due to the reputation required to comment on others' posts on most sites.

  • It's unfriendly or unkind.
    This comment is rude or condescending. Learn more in our Code of Conduct.

    Comments that contain harassment, bigotry or abuse or that are unfriendly or unkind should always be flagged. What you consider rude is subjective, but as a general rule if it is more likely to upset readers than it is to inform them, it qualifies. In deciding between the two flags, consider whether the comment is directly attacking a person (or the content they create) or a group. If so, it's probably appropriate to flag with the first reason. If it contains "pithy" jokes made at the authors' expense or "snarky" advice meant more to score points with the commenter's peers than to inform or educate it's probably a better fit for the second.

  • It's no longer needed covers a wide variety of different comments, including:

    • Obsolete/outdated comments. They served a purpose once upon a time but no longer: requests for clarification that've been addressed via edits, suggestions for improvement that were long ago heeded, etc. Don't worry about these if they're not displayed by default - if most readers don't see them, they're not causing any harm.

    • Chatty comments. They might be polite, friendly, or even informative - but have nothing whatsoever to do with the post! Whether tangential discussions or simply two friends chewing the fat, these are pretty benign - right up until they're being shoved in the face of every reader two years later. Again, don't worry too much about these if you don't see them by default.

    • Jokes, "thank you", etc. - not necessarily harmful in the moment, but distracting and annoying after the fact.

  • Something else covers everything else in a comment or comment thread that might benefit from a moderator stepping in to clean up. Be explicit about the problem that you see - don't assume it'll be obvious to the moderator.

If there are only one or two problematic comments on a post, just flag them individually; if most or all of an entire comment thread needs to go, just flag the post itself and suggest that it be purged.

Note: don't be too concerned if the occasional comment flag is declined; comment value is often subjective and moderators are encouraged to process flags quickly - in most cases, it's no big deal if comments persist a bit longer than needed. Declined comment flags do not count toward flag bans.

Moderator note: Moderator flags of all types on comments take action immediately, deleting the comment that is flagged - this can serve as a substitute for deletion on overtly abusive or unfriendly comments, as the flags then serve to keep a record of such behavior.

  • 36
    A lot of joke comments that aren't snarky or at the expense of anyone are being routinely deleted by moderators. If this is correct behavior, you might as well add that to this explicitly. If not, would you mind telling the moderators to lighten up and let users have a little fun?
    – Pollyanna
    Commented Aug 13, 2014 at 4:06
  • 16
    @Adam Davis: FWIW, I keep the jokes that are particularly clever and on-topic. The only problem is if there are too many joke comments with upvotes - those will certainly push away the more informative ones, and 5 is not a very generous threshold for displaying comments. Jokes can exist at the expense of no particular person, but then they wind up implicating other comments instead. Commented Aug 13, 2014 at 4:38
  • 7
    RE "moderators should just delete comments rather than flagging them". Wouldn't be helpful if mods flagged, since that leaves an audit trail for why the comment was deleted? Commented Aug 14, 2014 at 7:50
  • @MikePennington only if it's not obvious from the context, which... It should be in nearly every case.
    – Shog9
    Commented Aug 14, 2014 at 13:36
  • 3
    Flagging comments as obsolete is, in my experience, one of the biggest wastes of time, and usually results in the flag being rejected, no matter how obviously obsolete the comment is. In short there appears to be an inordinate and unjustified resistance to delete comments on the part of the moderators. Just my 2 cents. Commented Aug 14, 2014 at 18:00
  • 6
    What would be useful, I think, is when a comment is flagged as obsolete, that the author of the comment be notified so they can give it due consideration. Commented Aug 14, 2014 at 18:05
  • 1
    @LawrenceDol: Depends on the site, I think. We moderate comments fairly strictly on RPG.SE (i.e. making sure they're used for their intended purpose of requesting clarification or suggesting improvements - not, e.g., answering the question). I know scifi.SE is much more willing to tolerate comments of those sorts.
    – V2Blast
    Commented Apr 11, 2020 at 9:16
  • @Makyen I changed the link in the text you added to link to SO's privilege page, as here on Meta.SE the reputation requirement to comment is reduced to 5. Commented Nov 25, 2022 at 20:00
  • @SonictheAnonymousHedgehog Thanks for mentioning it. I'm fairly "meh" as to which site that link points to, as long as it links to the "comment everywhere" privilege page on some site. I agree that the rep requirement for that on MSE, and the fact that it varies per site, makes the situation more complex.
    – Makyen
    Commented Nov 25, 2022 at 20:15

When should moderators delete comments?

Same advice as for flaggers: when they offer no currently applicable constructive requests for improvement to the post.

Moderators may generally process comment flags without much deliberation: if it doesn't immediately appear to be needed, remove it; if it might be, leave it. There are almost always more useful things to do than to stress about comments.

Here are a few other tips for processing comment flags efficiently:

  • You may decline if you think the flag is too questionable.
  • Let another mod handle if the subject matter is not familiar to you.
  • If the flagged comments appear to be part of a larger, now obsolete conversation, then remove the entire conversation.
  • If many problematic comments are interspersed with a few allowable ones, purge the lot and then selectively undelete those that suggest improvements.
  • Don't worry about cleaning up benign conversations that don't appear on page load.
  • Do purge old, benign conversations that are in the face of every reader.
  • Prefer to use flag deletion to better document the comment as opposed to non-flag deletion.

When should moderators move comments to chat?

This option is available at any time from the mod menu on any post with comments:

move comments to chat option

How you use it depends on the situation. Keep in mind that you can only move comments to chat once for a given post, so consider carefully whether to use it or not. If the comments continue after moving them, you must resort to other options.

Handling an active tangential or off-topic discussion

Simply copying the existing comments to a chat room and leaving a link to it can serve to encourage participants (and others interested in continuing the discussion) to follow. If there's no pressing need to delete existing comments, leave them for context - though you may need to reinforce your encouragement by deleting any subsequent comments.

If the conversation has become extremely off-topic or distracting, you may wish to purge the entire set of comments and selectively restore those that remain relevant to the post.

Archiving a completed conversation

Sometimes a conversation can be useful in understanding the history of a post, but not terribly important otherwise for future readers. To remove the distraction, move the comments to chat, delete them, and then edit the resulting comment to point to the transcript rather than the chat room. Example:

Comment thread archived.

Note that the new room will be held to the normal activity requirements for room deletion and freezing. If there aren't at least 16 comments from two or more users being archived, the room will be automatically deleted after 7 days, which essentially has the same effect as just deleting the comments. If you do take the extra effort to archive a comment discussion, and there are not at least 16 comments from multiple users being archived, be sure to post messages in the new room to bring the total up to 16 (17 including the automatic Feeds message).

  • 1
    Looking at the list of options here, it seems that if there are useful comments which shouldn't be moved and a discussion which should in the same comment thread, the moderator has no good options. Is that correct, or does "thread" mean that the moderator gets to see a tree structure and move only one branch? Commented Aug 13, 2014 at 8:49
  • 13
    This needs to be changed. Mods should be able to move any conversation, no matter how long and how many people are involved, to chat.
    – Raphael
    Commented Aug 13, 2014 at 11:49
  • Moderators are able to control what gets moved by simply deleting anything that shouldn't be one place or the other after comments are copied into chat, @peter
    – Shog9
    Commented Aug 13, 2014 at 13:18
  • 3
    Technically, they can @Raphael - whether that's a good idea or not depends on the situation. I've been watching this for a couple of years now, and IMHO there's rarely any reason to start a chat room for a single person talking to himself or a discussion that petered out months ago.
    – Shog9
    Commented Aug 13, 2014 at 16:17
  • 2
    So does "move" mean "move", or does it mean "copy"? Is the entire comment list copied to chat so that comments (all or some) may be deleted, or is the entire comment list moved to chat? If the latter, can comments which are relevant in both places be undeleted on the post? [Sorry, a previous comment probably answers this, but I'm confused by the use of the word "move"] Commented Aug 13, 2014 at 18:07
  • 1
    It's The Prestige's version of "move" @Andrew - IOW, copy with the expectation that the originals will be removed at some point.
    – Shog9
    Commented Aug 13, 2014 at 18:24
  • @Shog9 What, how can we move comments to chat? Regarding scenarios, I have experienced a lot of comment threads that were long without the "move to chat" link popping up. Also, it would be nice to preemptively move only a few comments to chat if there's clearly a meta discussion evolving as opposed to having to wait (and then remember and revisit!) for the damn link to appear.
    – Raphael
    Commented Aug 14, 2014 at 7:24
  • Sorry, @Raphael - this was supposed to be announced by now, but we're having a bit of trouble with the blog. I've added a crosslink in the answer. The button only shows up in the UI when there's a system flag raised, but we may tweak the threshold for that or add the option elsewhere in the future - depends on how y'all end up using it. As for moving a select few comments - that could be achieved via careful deletion + undeletion, although I'm not sure it's a good idea.
    – Shog9
    Commented Aug 14, 2014 at 14:10
  • @Shog9 is this flag raised if 20 (or however many) comments total are posted, or if 20 that haven't been deleted are present? Commented Aug 14, 2014 at 14:22
  • Total, @MonicaCellio
    – Shog9
    Commented Aug 14, 2014 at 14:38
  • @Shog9 Thanks for the reference! Looks good, even though the trigger criterion is "dumb" and the value quite high. Commenting there.
    – Raphael
    Commented Aug 14, 2014 at 18:45
  • 3
    This answer is supposed to be advice about what moderators should do. It seems to imply that if there is a long comment thread where 50% of the comments are fine and useful, but 50% of the comments are part of an ongoing conversation that's not relevant to the post, then all comments should be moved to chat (copy to chat, delete all comments). I don't think that's the best advice to give moderators. Instead, in that situation, I think it would be more suitable to copy all comments to chat, then clean up the comment thread by deleting most comments and keeping only the relevant, useful onexs.
    – D.W.
    Commented Aug 14, 2014 at 20:29

When should I delete my own comment?

When it offers nothing of value to either the author of the post or to future readers. This is particularly important when the comment is shown by default on page load - if readers need not opt-in to reading it, it should offer them something of value.

Try to avoid leaving long comment threads "broken" by deleting your comments while leaving replies to them. If a long thread has become irrelevant, coordinate the removal by suggesting deletion to the other participants and giving them time to respond before removing your own comments. If the thread is old and the participants have moved on, flag the post itself for moderator attention and suggest purging - be sure to explain why!

  • 21
    I think we should feel free to delete our own comments at any time without needing to consider what else is in the comment thread. I say this because it reinforces the transient nature of comments and the need for askers and answerers to incorporate any useful content from them into their main posting sooner rather than later.
    – PolyGeo
    Commented Aug 13, 2014 at 8:15
  • 12
    Eh; if you engage someone in conversation, I think it's just polite to let them know that you're disengaging rather than abruptly deleting your side of the discussion. You can argue that folks shouldn't be getting into extended discussions in the first place - and you're right - but that's no excuse for being rude after the fact. An awful lot of hurt and confusion could be avoided if folks just took 5 seconds to talk to each other respectfully now and then - if you say you're done and then come back later and delete your comments then that looks a lot less sketchy.
    – Shog9
    Commented Aug 13, 2014 at 16:15
  • 12
    A middle road may be to delete the comments, and add a new comment explaining why you have removed them, to avoid the impression that you left because of dissatisfaction in the conversation. Commented Aug 13, 2014 at 16:56
  • 1
    Excellent point, @Eric - feel free to edit that into the answer here...
    – Shog9
    Commented Aug 13, 2014 at 18:22
  • 1
    My comment above is on assumption that the sole purpose of comments is to improve the Q or A rather than to engage in a discussion/conversation. For me a comment is usually (Meta being the exception) a one way request for clarification, a suggestion for how to clarify, or already assumed minor/transient which coincides with the dot points you cited from the Help. Here may explain more where I come from.
    – PolyGeo
    Commented Aug 13, 2014 at 21:46
  • 2
    If you avoid creating long comment threads (kudos), then the paragraph starting with "try to avoid leaving long comment threads broken" doesn't apply, @Poly.
    – Shog9
    Commented Aug 13, 2014 at 21:53
  • 3
    "If the thread is old and the participants have moved on" Wait, people don't log in to SE at least daily? Shame on them :) Commented Aug 14, 2014 at 1:56
  • 2
    I think the better solution - rather than waiting to delete your own comments, even after the issue is resolved/the conversation is over - is to just delete your own comments and flag the other person's comments as "no longer needed".
    – V2Blast
    Commented Apr 11, 2020 at 9:18

When should moderators edit comments?

Almost never. Comments have no publicly visible revision history (the changes are logged in case of abuse, but these are only visible to moderators). Therefore, it is critical that moderator edits do not misrepresent the author's meaning or intentions. Edits may be appropriate in the following scenarios:

  • To fix typos or other minor errors that the author has written a second comment to correct (at which point the second comment can be deleted). This is usually a waste of time, but can be worthwhile in particularly embarrassing scenarios or with a broken link.

  • To remove rude or inflammatory language from otherwise-worthwhile comments. Again, it is very rare that this is worthwhile – normally, rude/inflammatory comments should be deleted, but sometimes the rest of the comment is valuable enough to be worth preserving. Examples:

    • -1: I'm downvoting you as hard as I can, because this answer contains an error on line 5: you should never poke bears with a sharp stick just to see if they're still alive.

      Removing the italicized text may be worthwhile to allow readers to focus on the potentially life-saving advice without sparking a voting war.

    • The onset of frostbite can be subtle; therefore, to this advice I would also add that, when spending the night in harsh conditions, it is important to prepare ahead to protect yourself from the elements. Also, your mom.

      Again, remove the bit in italics.

    When editing comments for tone, you should strive to make the smallest edit necessary to correct the problem. You should also generally leave a comment advising the comment's author against such faux pas in the future! Such commentary helps to avoid the appearance of deceit.

  • To fix a comment that you just converted from an answer. Sometimes, converting an answer to a comment destroys the formatting or cuts off parts of the post. You can and should fix those issues, but make sure to keep the post’s content intact.
  • A case study in the perils of putting words into people's mouths - over at ux.stackexchange.com/a/70158/47336, a well-meaning mod tried to tone down some potentially rude language I'd used (I called parts of an answerer's argument "ridiculous" and "stupid", but post-editing the words used are "inappropriate" and "unjustifiable"). I'm sure some would agree the result is politer, but I'm embarrassed to have it in my name; the version I actually wrote feels to me like blunt but respectful criticism of technical content, while the new version feels like moral criticism of the answerer.
    – Mark Amery
    Commented Mar 1, 2015 at 13:40
  • "Comments have no visible revision history" this is not so true anymore. the guidance here may need updating.
    – Double AA
    Commented Mar 16, 2017 at 17:17
  • Finish reading the sentence, @DoubleAA: doesn't much help if mods can see it if the person whose comment you edited can't. (when I wrote this, the history was only available by directly querying the DB, which was admittedly even worse from the perspective of catching abuse, but even with the current mod UI it's easy to "gaslight" a user if you're not careful. FYI: the only reason there's a history here at all is that we once had a moderator decide it was a good idea to go around editing comments that criticized him...)
    – Shog9
    Commented Mar 16, 2017 at 19:19
  • I think now where mods can see it is a big change from before where it was (allegedly) somewhere in your databanks. Now if someone complains other mods can peer review and it can easily be reverted. This is still not full transparency, but it's a big step towards accountability and can justify a slightly more lax attitude towards editing comments in more borderline situations. (I hope that mod isn't a mod anymore...)
    – Double AA
    Commented Mar 16, 2017 at 19:22
  • 3
    I would not ever recommend being "lax" with this feature, @DoubleAA. When you can't see what's been changed - and especially if you're new to Stack Exchange as a whole - seeing your words edited can be extremely unsettling; I've gone so far as to leave inline editing notes ([ removed inflammatory language --Ed. ]) to forestall this.
    – Shog9
    Commented Mar 16, 2017 at 19:24
  • 'being lax' and '[being] slightly more lax in more borderline situations' are quite different.
    – Double AA
    Commented Mar 16, 2017 at 19:25
  • It's always a judgement call, @DoubleAA. Just try to keep in mind the perspective of the authors.
    – Shog9
    Commented Mar 16, 2017 at 19:27
  • 3
    The main reason I edit comments on RPG.SE... is when people comment on a question with "Related: [bare URL]". I just edit the question title into the comment so people know where the link leads (since the end bit of the URL is truncated in the displayed text of a bare URL). Other than that, as this answer warns, mods should be very careful in how and when they use this ability.
    – V2Blast
    Commented Apr 11, 2020 at 9:20

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .