What are the guidelines and/or time table for comment deletion? I feel some comment threads get pruned way too early compared to deletions on other stacks. While comments are not meant to stay forever, on here they disappear too soon. Maybe overzealous comment deletion.
The same guidelines as everywhere on SE, which means not so many other than that comments are not for extended discussion irrelevant to the question.
There are many comments that are downright useless or obsolete on the matter:
- Impolite comments that may not be downright offensive but scratch the boundary of constructive criticism. (Flag as
not constructiveif not
- Comments asking for clarification and/or edits that have already been incorporated into the actual post. (Flag as
- Old comments discussing long-decided policies inspired/related to the question but which have since been resolved. (Flag as
"Thank you" and "+1" comments that don't mention any actual specific reasons why the post is so valuable (or stupid reasons like "+1 for that funny phrase that made me chuckle"). Those users have already expressed their appreciation by voting on the post or accepting the answer. (Flag as
Though, it can be useful to leave "Thank you" comments alive when they point out that the answer is absolutely correct but it hasn't been accepted. In this case those comments can serve as entry points for enlightening the likely inexperienced users about the acceptance feature.
- Overly annoyed complaints about unexplained downvotes. While asking why your post was downvoted and where its problems are can help to clarify matters and improve your post, doing so in a rather annoyed and huffy tone rarely helps the cause at all. (Flag as
- Diverging discussions inspired by the question but rambling on about a topic entirely irrelevant on the matter. Those tend to clutter up the comment section leading to an extended trail that is of no actual use for anyone interested in the question. For such discussions chat is the perfect tool. (Flag as
too chattyor even
- Answers to closed questions in comments. Those are discouraged on SE due to being detrimental for encouraging users to improve their questions and adapt to the site's rules. (Flag as
Now this doesn't mean that any side comment that's not about the question is to be deleted immediately. Sometimes there are interesting side notes on a question, providing related, if not directly relevant, information. If it has actual information value and touches a topic related to the question, then it sure has some value and as long as they don't devolve into extended discussion, they don't pose much harm. That doesn't mean they couldn't ever get deleted, but it lowers their chances to be.
As for when they get deleted, there's no actual guidelines on that either. The moderators likely won't just surf old questions/answers and see if they can delete some comments. However, there are some factors that might favour comment deletion:
- A flag has been issued on the comment. This of course sheds light on the comments and the validity of the flag has to be assessed and acted upon accordingly. This may result in additional comments on the whole thread to get deleted due to the attention spent on its comments.
- A question has an unnaturally large comment section. This could point to extended discussion that more often than not is of no use anymore and can thus be pruned for conciseness and relevance if necessary.
- There is additional attention spent on Hot Network Questions, which often attract many 101 users that might have something "interesting" to say on the matter (while not interesting enough for an actual answer). Not all of those comments are useless of course, but they can sometimes be of very marginal and chatty nature, especially due to our supposedly "trivial and funny" site topic in general. So we keep an eye on those questions and try to inhibit such discussions early on before they get out of control, especially since those questions have to show us from our best side.
But at the end of the day, it's still a game of luck when a comment is deemed irrelevant and deletable. This is not to say that the moderators just throw a dice for each comment, only that pondering about why this comment got deleted and that comment was allowed to stay when you think it should be the other way around is of not much use for your sanity. Don't grow too attached to your comments, especially if they are of rather marginal nature.
This however doesn't mean you should not bring it to meta if you really feel a highly valuable comment has been deleted without any reason or if your flag has been declined while you strongly think it should have been validated. Don't feel discouraged to bring up any specific examples where you see the moderators possibly violating a sane comment policy (as long as it's not just "but my joke was totally funny, why you no let me express myself?" ;-)).
As a further note, if you yourself choose to delete your own comments for any of the above reasons, please try to keep an eye on the surrounding comments and if they still make sense without yours. Feel free to flag any of the other users' comments as
obsolete if they are no longer relevant then.
And in general, if you choose to help in comment moderation by appropriate flagging and happen to come across a huge comment discussion under a single post that's largely irrelevant, feel free to just flag the post itself with a custom moderator flag and an appropriate message if you don't want to indulge into flagging each and every single comment.