I am aware that sometimes comments are deleted as a result of single flag if they contains some blacklisted words/phrases, as explained in several posts on this site. (For example: What is the SE version of Seven Dirty Words?, flagged comments disappear instantly … what's going on? or How is it possible that a single user who is not a moderator can delete a comment?.)

Question: Is a comment sometimes deleted by a single flag (or even without flagging) also if the system identifies it as some kind of a response to a previous comment after the previous comment is deleted? (Even if the comment does not contain some blacklisted phrase.)

In other words: Are there also some situations other than blacklisted phrases when single flag suffices for deletion? Are comments sometimes deleted simply after deletion of another comment, without any intervention from another user, owner of the comment or moderator?

I am asking this as a follow-up of a previous discussion on Mathematics Meta: Why did flagging a comment for deletion made it disappear immediately?

The OP described the situation (the way they see it) in these two comments as follows:

It seems that the algorithm is roughly the following: user A posts something, user B writes a comment under this post, user A answers with another comment containing a ping @B (which allows the SE software to interpret this last comment as an answer). Now, if user B deletes his comment, user Community automatically deletes user A's answer.

The described comments were originally under this answer. However, the comments in question are now deleted, so they cannot be seen by regular users.

EDIT: I will add that in situation described above, user A confirmed that they did not delete a comment. According to a mod, the flag is displayed as handled by community user. (For more details see the above link.)

This was done as an experiment in comments below this question:

Let's try it then, I'm user B here ... I guess ... - rene

@rene So here is my "reply comment". If I understood the description given by other user, you should now deleted your comments and see what happens. (Possibly, if this does not suffice, flag my comment as "no longer needed" to see whether one flag suffices.) I hope I haven't use a problematic word here - which would make this into a "1-flag comment". - Martin

Well, .... no can do ... no repro, and I might end-up with a declined flag ;) ... proof that I flagged: i.stack.imgur.com/sqlTe.png - rene

Thanks for the experiment @rene. Since the first comment was deleted I have summarized this exchange in the post. - Martin

  • Well, .... no can do ... no repro, and I might end-up with a declined flag ;) ... proof that I flagged: i.stack.imgur.com/sqlTe.png
    – rene
    Jan 5, 2018 at 17:28
  • Thanks for the experiment @rene. Since the first comment was deleted I have summarized this exchange in the post.
    – Martin
    Jan 5, 2018 at 17:34

3 Answers 3


In this case, the mystery is clarified when you look at the content of the comment.

Deleted comment reading "Yes they are. Remember the maps go from larger n to smaller, and the map Xn+1→Xn has Lipshitz constant 1/2. – Chad Groft Dec 29 '17 at 22:57"

While it's not obvious at first, the comment was actually single-flag deleted because it contained one of the words that triggers immediate deletion - "shit" - inside the name "Lipshitz".

I've tested this to confirm the behavior.

So, there's not really anything new here, just an overenthusiastic search for keywords.

  • 2
    You folks at SE don't have any plans to fix this wrong behavior, do you? For instance by implementing a whitelist of "words that contain offensive substrings but are not offensive by themselves"? In my view it's a bug in the platform. Aug 3, 2018 at 2:26
  • 4
    I remember people misusing this Scunthorpe Problem in the SE system by flagging comments by moderators with the wording Please don't add the same answer to multiple questions. Answer the best one and flag the rest as duplicates. See Is it acceptable to add a duplicate answer to several questions?" as no longer needed (the word "accept" in "acceptable"). It's better if it's fixed @FedericoPoloni. :) Aug 3, 2018 at 17:00

No, replies aren't auto-deleted when the earlier comment is deleted. If they were, it would make moderation of long comment threads easier and I would have noticed. :-)

I see two patterns that could produce behavior like what you described. (Whether either is actually what happened in your case, I can't say.) One is that A and B are having a conversation, and one of them considers it resolved (the post got edited or whatever), deletes his own comments, and flags the others. An observer sees several comments getting deleted together.

The other case is where A and B are having a conversation and one of them flags the other's comments without deleting his own. (You can't flag your own comment, so there's no good way to avoid breaking the thread -- either you delete yours right away, break the thread, and wait for a moderator, or you don't delete anything, flag what you can, and hope a moderator will also clean up yours.) In this case, it can happen that a moderator just acts on the flags without noticing the context, so one side of the conversation gets deleted and the other not.

  • 1
    one of them considers it resolved, deletes his own comments, and flags the others That's exactly what I always do.
    – Jan Doggen
    Jan 5, 2018 at 19:24

There's nothing that connects one comment to another. An auto-delete due to a flag only acts on the single comment flagged.

If the two comments were deleted within a short span of time, I can think of several explanations:

  • one of the commenters saw the other comment was deleted (maybe they flagged it) and so deleted their own comment
  • a moderator was acting on one flag and saw the other comment in response, so deleted it
  • both comments were flagged and a moderator acted on them simultaneously

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