It has long been a mainstay of the stack exchange ethos that comments should not be used for extended discussion and even changes to the UI do not change this according to some.

Unfortunately I do not think that we are very good at keeping to this ethos on this stack, and it causes some friction when long comment threads are moved to chat. I believe it is the nature of this community that we are all enthusiasts of an interesting topic that discussion is generated but this is exactly what chat was disigned for.

A recent example is nuclear propulsion - which is clearly an interesting concept to discuss, and has ended up with huge swathes of various discussions in the comments.

So the question is, are you as a community wanting to have discussions in comments? Should the moderators actively clean this up and move it to chat?

  • $\begingroup$ The answer underneath that meta post that you reference is a clear one: only flush in case of low value. $\endgroup$
    – Koyovis
    Commented Dec 12, 2017 at 22:58

4 Answers 4


moderators on other SEs will actively move extended discussions in comments to chat. with a stock message:

Comments are not for extended discussion; this conversation has been [moved to chat](link to chat room created).

doing that will tend to kill the discussion, but SE was never meant to be a platform for extended discussions anyway.

  • 4
    $\begingroup$ Please be aware that we know what other mods usually do :P The question here is: do you users want us to keep in line with the rest of SE, or do you want us to deviate from the norm? We currently are at an impasse because the previous "lack" of moderation has apparently given the expectation that comments are not removed, while instead there are people (mostly coming through the HNQ list) that actively go around to hunt for comments to flag for removal, and those don't even get moved to chat. $\endgroup$
    – Federico
    Commented Dec 1, 2017 at 14:25
  • 1
    $\begingroup$ Moving long comment streams to chat allows those who wish to keep the discussion going a nice place to do it. +1. $\endgroup$ Commented Dec 4, 2017 at 15:47
  • $\begingroup$ Oh yeah it works really well! For instance the chat linked in the comments under this question $\endgroup$
    – Koyovis
    Commented Dec 10, 2017 at 15:03
  • 1
    $\begingroup$ @Koyovis I assume the "it works really well" was intended as sarcasm, since that link is now dead? $\endgroup$
    – reirab
    Commented Dec 12, 2017 at 19:36
  • 1
    $\begingroup$ @reirab yes, when I joined this site 8 months ago I had a good time going through 3 years worth of questions, amswers, and the comments on them from all of the community. It's a good format. $\endgroup$
    – Koyovis
    Commented Dec 12, 2017 at 21:40

My view is there is no really good solution. Until we find one, we should accept comments to be deleted when they take the form of a sustained discussion.

That said,

  • Comments are useful to ask for clarification, or to provide additional elements, even bases for a full answer. They should be removed by their author when they are not relevant anymore (the post has been clarified or completed, or the answers have taken the elements into account).

  • Comments are also useful to challenge an answer which is incomplete or dubious. Indeed challenging is prone to start a discussion, and this discussion should be moved to the chat by moderators, based on their own evaluation.

  • Comments that don't focus on the post, but start a discussion on they own topic are perfect candidates for being moved to the chat.

  • We should take into account that comments are also in practical the main tool we have to socialize and create a community. The chat isn't comparable (e.g. in time spent).

Many comments should be temporary, at some point they stop being meaningful, they should be removed without scruples if the author forget to do it themselves. On that aspect I must say the system prevents you to do it in mass (I believe you can delete comments on 20 posts per day).

The problem with the chat is it is disconnected from the main site, and some comments need to be in plain view, as they are totally related to the posts and can be upvoted. I wonder if SE shouldn't include a small chat at the question level, e.g. on the right side of the page, not too wide. Maybe at the post level, if we wanted to comment on a specific post. This would clearly separate comments and Q/A, but would allow for useful discussion. Maybe this has cons I don't see, and anyway it's not available today.

  • $\begingroup$ Regarding particularly your second and third bullet points, I would like to just point out that while it's easy for a moderator to move all comments on a post to chat, moving select comments to chat is far more work. I would expect mods to just shrug and say "not worth the effort", and either move all comments to chat, or purge them outright. $\endgroup$
    – user
    Commented Jan 13, 2018 at 21:48

I would say that the answer to this is dependent on the situation.

Funny Comments

At least judging from my (somewhat long) experience with this stack, it allows for somewhat more humor/wit than most, even when it's not directly related to clarifying or suggesting an improvement to a post. Personally, I like that. I don't personally feel that a witty comment or two on a question or answer hurts anything and I don't think deleting them helps anything in most cases. On the other hand, if it gets to be more than a few on a given post, at least some of them should probably be deleted. This is, of course, assuming that the humorous comment in question isn't offensive. Comments that violate the Be Nice policy should be deleted immediately regardless of humor.

Regarding the witty/humorous comments, at times, I think it can be a subjective judgment call on which ones get deleted. If there's a lot of noise in a given comment section, removing all of the humorous comments may be useful. On the other hand, if there were one or two that I found particularly witty and/or which attracted a lot of upvotes, I'd personally prefer for those to remain. I don't think having a sense of humor on the site is a bad thing.

Relatively Brief Discussions of Relevant Information

There have been lots of times on this site where a comment posted on an answer has resulted in a relatively brief and usually informative discussion of that topic, usually either to clear up a misconception of the comment's author or of the answer's author. Again, if these are kept relatively brief (say, no more than 4-6 comments) and they're informative, I think it's fine to leave them unless one or both parties desires for them to be deleted or the comments on that answer are getting too long.

In some cases, the answer's author can edit the answer to address the issue mentioned in the comments and, in those situations, it's preferable for the answer to be edited and then the comments deleted. However, in other situations, the side issue may not be directly relevant to answering the question and, thus, might not belong in the answer. In the latter set of cases, I think it's fine for these to remain in the comments.

One problem that can arise when these comments are moved to chat is the one that Koyovis mentioned in a comment on another answer here: the chat room can end up being deleted. As Koyovis pointed out, this answer is a good example of that. As Federico pointed out in the comments, these rooms get automatically deleted if they do not contain more than 15 comments by at least 2 users after a period of 7 days of inactivity. A user who was very knowledgeable in the subject had posted comments explaining why a given answer was wrong. The comments were moved to chat, but the chat link is now dead, since the thread contained less than 15 comments. In this case, it was a user who flew the F/A-18 discussing the launch of missiles from a fighter, but now his comments are gone (and he is unfortunately no longer an active user.) Unfortunately, moving the comments to chat was not useful in this case.

Longer Discussions

When the discussions start to get truly 'extended' (say, greater than 4-6 comments in a discussion,) then I think there's a better argument for moving them to chat. At least on other SE's, though, I've heard that comments on a given post can only be moved to chat by a mod once. (Someone feel free to correct me if that's not accurate, but I seem to recall reading it from the mods of other stacks.) Given that, I'd recommend that the mods be careful about not moving the comments so quickly that a bunch more end up being posted with the mods then having no choice but to leave them or delete them.

When an extended discussion does need to be moved to chat, I would also recommend that the mods be a bit judicious about which comments are moved. For example, if there's a comment with a given valid criticism of an answer which then sparks a lot of discussion, it may be better to leave the original comment on the answer even after everything else is moved to chat. This way, others who don't bother following the link in the chat will be aware of the potential problem(s) with the answer. Of course, if the answer is actually edited to address the issue(s), then there's no reason for the comments to remain.

The Nuclear Option

(OK, I just liked that title.)

Regarding the nuclear question in particular, the comments on the question seem to have a low signal-to-noise ratio. A few contain interesting information, but, overall, it's not very focused and, at least in my subjective opinion, none of them really stand out as a comment that should stay. I'd not personally miss them if a mod nuked them all.

People Flagging Comments Just to Flag Comments

In a comment it was mentioned that

there are people (mostly coming through the HNQ list) that actively go around to hunt for comments to flag for removal, and those don't even get moved to chat.

If the comments truly are useless, I can understand this. If the comments are not useless, then this behavior doesn't seem very useful and, personally, I'd recommend rejecting the flags. Dogmatically enforcing rules that were created primarily for SO just for the sake of enforcing rules is not useful. And it's even less useful when it's coming from people who rarely even visit Aviation anyway and are only here because of an HNQ question. If someone is going out of their way just to find comments to flag, I wouldn't feel too bad about rejecting their flags in hopes that they'll find something more constructive to do instead in the future.

  • 1
    $\begingroup$ You've stated very well that good judgement should be used. The first link in OP is to an old discussion on Meta on exactly this topic. The result of that discussion also seems to be that good judgement should be used. But now people are advocating that everything over 20 should be flushed, because it is flagged. It's flagged for attention for applying good judgement, not for automatic flushing. The site could do that automatically, without a mod intervention. $\endgroup$
    – Koyovis
    Commented Dec 13, 2017 at 2:16
  • $\begingroup$ For the "deleted chat" problem, there is a simple solution. If you are interested in reading the deleted chat, simply flag the original post with a custom mod flag asking for the un-deletion of the chat. I have just done it with the one you mentioned in this post. $\endgroup$
    – Federico
    Commented Dec 14, 2017 at 11:19
  • 1
    $\begingroup$ "comments on a given post can only be moved to chat by a mod once" that's correct. "I'd recommend rejecting the flags" we reject already lots of flags, particularly on "funny comments". $\endgroup$
    – Federico
    Commented Dec 14, 2017 at 11:31
  • $\begingroup$ @Federico Good to know. I wasn't intending that as a criticism of current moderation, by the way, just stating what I'd personally do with them in that case. :) $\endgroup$
    – reirab
    Commented Dec 14, 2017 at 13:29
  • $\begingroup$ no problem. Even if it was criticism, it's good to have it, it keeps everyone sane. $\endgroup$
    – Federico
    Commented Dec 14, 2017 at 13:30
  • 1
    $\begingroup$ ah, I had an extra look at the "deleted chat" thing: only chats with less than 15 messages can get deleted (i.e. those created when 2 people are chatting by themselves), a chat created by a mod moving 20+ comments does not get deleted chat.stackexchange.com/faq#retention The one you linked has only 8 messages, so it gets deleted automatically. $\endgroup$
    – Federico
    Commented Dec 15, 2017 at 8:06
  • $\begingroup$ @Federico Ah, ok. Thanks for looking that up. I wasn't sure what the criteria was on that. $\endgroup$
    – reirab
    Commented Dec 15, 2017 at 15:31
  • $\begingroup$ Just out of curiosity, I went to look for our oldest chat created by a mod moving comments to chat. It is still there: aviation.stackexchange.com/a/8952/1467 $\endgroup$
    – Federico
    Commented Dec 15, 2017 at 20:53

It's a complicated issue, any sweeping one-liner won't be a good solution. Comments exist for a reason, and a good comment does not have a Use By Date.

Comments can

  • Improve the quality of the answer and provide a frame of reference. Nobody thinks of everything.
  • Challenge the knowledge of the answerer. Nobody knows everything.
  • Point out inconsistencies. If the comment is valid and the answer is not edited, it loses quality if the comment is removed.

Comments can also be:

  • Disturbingly patronising and intentionally downgrading. I personally have no problem with these being removed immediately. Better yet, make a separate chatroom where all degraders can put each other down. I will never visit it.
  • Inconsequential conversation. Best done in chat.
  • A lengthy discussion between two or three parties that mostly may be uninteresting for the rest of us.

The questions and answers are presented in an overview that lists the five most up-voted comments. To see more, one has to click on a link. The mechanism is already there, why move everything to a chat room that dies and where newcomers cannot see the immediate connection and the most up votes answers? It took me a while before I figured out how chat worked on this site, it is quite obscure. The existing system is a good system - after clicking the See More link, we then can choose to read the other comments or disregard them after the first four words. This is kind of like pointing out that there is an OFF button on a TV: you don't have to read them. You may choose to though, you may find it interesting what others have to say.

The sites grow organically, from a set of initial rules. The Aviation SE is still relatively small and has lingered for a long time in the Experimental phase. It has apparently had very little moderator input in the past, and managed to do quite well nevertheless. Aviation is a subject with a broad interest amongst the general public, and some questions and answers can attract many viewers. We still don't have many experts here, and aviation physics is not a subject taught in high schools like theory of relativity is. Many interested viewers, few experts - all mechanisms that keeps them honest and focussed are good, and members who join the site after the reference framing has taken place can still take on board the broader picture.

In my opinion:

  • Any solution should consider the quality and relevance of the post before removing it. Yes it's still somewhere when it is in a chatroom - somewhere dark, odorous and unwelcoming.
  • The system flags for human intervention, it does not automatically move all comments to chat. That is for a reason.
  • Comments exist for a reason, and a good comment does not have a Use By Date.
  • 3
    $\begingroup$ "somewhere dark, odorous and unwelcoming" that's your opinion. I always preferred chat to comments, for example, you have more space, you can link to the comment you are answering to, it's easier to read, I get to know other users more, I get to talk with users that do not participate any more on the site, etc. $\endgroup$
    – Federico
    Commented Dec 5, 2017 at 7:54
  • $\begingroup$ @Federico The Hangar is a good place, quite relaxed there. I'm specifically referring to the chatrooms that are comment dungeons. $\endgroup$
    – Koyovis
    Commented Dec 7, 2017 at 0:07
  • $\begingroup$ I don't mean only hangar, as you can see, I had quite a lengthy conversation in one of the latest "comment generated" chats: chat.stackexchange.com/rooms/69004 $\endgroup$
    – Federico
    Commented Dec 7, 2017 at 8:13
  • $\begingroup$ A conversation like that should be conducted in chat, absolutely. Why was the conversation so lengthy in the first place? $\endgroup$
    – Koyovis
    Commented Dec 7, 2017 at 8:22
  • $\begingroup$ ¯\_(ツ)_/¯ I can't predict the length of a conversation before it happens and I don't have an interest in analysing it post-factum $\endgroup$
    – Federico
    Commented Dec 7, 2017 at 8:28
  • $\begingroup$ Two parties are required for lengthy conversations... $\endgroup$
    – Koyovis
    Commented Dec 7, 2017 at 8:35
  • $\begingroup$ I upvoted your answer. Although you've deleted a good and informative comment of mine. $\endgroup$
    – user7241
    Commented Dec 12, 2017 at 7:34
  • $\begingroup$ @jjack Feel free to up vote or down vote as you like. Comments should add to the quality of the question. $\endgroup$
    – Koyovis
    Commented Dec 12, 2017 at 7:44
  • $\begingroup$ @Koyovis Mine did. I explained how the method was called that the person answering was suggesting. And what the requirements are for the method to work. $\endgroup$
    – user7241
    Commented Dec 12, 2017 at 7:54
  • $\begingroup$ @Koyovis Sorry if it wasn't you who has deleted my comment. I got the impression because your comment with respect to mine still stood while mine had disappeared. $\endgroup$
    – user7241
    Commented Dec 12, 2017 at 10:06
  • $\begingroup$ @jjack I'm not a moderator and can only delete my own comments. Also, I'm not interested in arguments. $\endgroup$
    – Koyovis
    Commented Dec 12, 2017 at 10:27
  • $\begingroup$ @jjack Only users with the diamond after their name (see Federico's above for example) can delete the comments of other users. $\endgroup$
    – reirab
    Commented Dec 12, 2017 at 19:41
  • $\begingroup$ I generally agree with this answer, though "a good comment does not have a Use By date" is not universal. Many good comments have a temporary need (e.g. suggesting edits.) However, I completely agree that not all comments should be temporary. $\endgroup$
    – reirab
    Commented Dec 12, 2017 at 19:43
  • $\begingroup$ @reirab Thanks, I hadn't noticed that yet. Should stop randomly blaming people... $\endgroup$
    – user7241
    Commented Dec 13, 2017 at 3:46

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