Recently I've noticed some of my comments and exchanges under posts end up disappearing without any reason. What is happening? I reckon a moderator might be deleting them, or they are being randomly flagged, but these were neither part of an extended discussion, which typically get removed after a while, nor eligible for any of the common comment flags (such as being unkind, spam, etc).

  • Has anyone else experienced this? It would be nice to know at least why they are being so promptly deleted. I understand that sometimes when a comment has been addressed and therefore is no longer relevant, then it can be removed. But other times when it's praising a good answer, or suggesting an edit, or criticising something, it would be nice to not have them deleted, as after all it's mostly via comments that we discuss/communicate here in SE and form a cohesive community. Additionally, commented suggestions might also be useful for other and future readers that might also write questions or answers.

I think it would be helpful not to have comments aggressively removed if they are not part of extended discussions, nor mean-spirited. Moreover it's often difficult to judge if a comment is truly no longer relevant, so maybe, it might be best to simply leave them be.

1 Answer 1


I might have deleted some of them; especially when cleaning up large comment threads, it happens that I inadvertently delete the one that was worth keeping. Other comments might have been deleted because they contain certain keywords like 'thanks' or '+1', causing them to be deleted after a single comment flag by any user. There's no official list of those keywords (it varies per site) but you can find more information in this Meta Stack Exchange post and related topics.

It's worth keeping in mind that

Comments are temporary "Post-It" notes left on a question or answer.

(emphasis mine)

and there are some guidelines about when and when not to comment:

When should I comment?

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).

When shouldn't I comment?

Comments are not recommended for any of the following:

  • Suggesting corrections that don't fundamentally change the meaning of the post; instead, make or suggest an edit;


  • Compliments which do not add new information ("+1, great answer!"); instead, upvote it and pay it forward;


  • Secondary discussion or debating a controversial point; please use chat instead;

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