This question is about suppression of threads of comments by moderators, moved to chat with the message "Comments are not for extended discussion; this conversation has been moved to chat", with link to the chat.

A recent example is this post.

I'm not addressing the case of polemical comments or disputes moved to chat such as this question, or deleted.

My impression before the moderator election is that this has been done quite too often on MathStackExchange, and was quite happy that this kind of moderation is performed... with moderation (only with very large number of comments, selective choice of comments moved to chat). I find the comments as being part of the MathOverflow reading. Is a more severe way of acting really needed? What are reasonable criteria to move a comment conversation to chat?

In the above example, first there is visibly a problem with the question in view of the vote balance, and, second, reading comments (now moved to chat) is instructive. I would really see a severe streamline of the chat conversations as a deterioration of the site.

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    $\begingroup$ I'd say the comments in that example are more than just "instructive". They truly advance understanding of the mathematics. I hope some knowledgeable user will edit the question to reflect the progress that now is available only in the chat (or delete the question entirely, if that seems like a better idea). $\endgroup$ Commented May 5, 2021 at 9:53
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    $\begingroup$ In case somebody wants to see where comments were moved to chat, here is a query which shows comments containing "moved to chat": main, meta. (The status from the last update of SEDE.) $\endgroup$ Commented May 5, 2021 at 10:11
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    $\begingroup$ The purpose of moving a conversation in comments to chat is not suppressing it, but rather moving it to a more suitable place (at least as far as I can tell, this is SE's intention behind the possibility to move a comment thread to chat). However, I quite understand if people feel different about this. Some related discussion (on Math.SE's meta) can be found here. As to the post in question, I undeleted the comments again. $\endgroup$
    – Stefan Kohl Mod
    Commented May 5, 2021 at 10:47
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    $\begingroup$ Personally I don't like the whole SE "move comments to chat" thing at all. If the comments are bad they should be deleted, and if they're ok then they're not doing any harm sitting there minimized. $\endgroup$ Commented May 5, 2021 at 16:39
  • $\begingroup$ Shouldn't the title be "Deletion by moderators of comments" or perhaps "Moderators' deletion of comments"? $\endgroup$ Commented May 5, 2021 at 17:44
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    $\begingroup$ My own attitude has been to be relaxed about comments if there is a real mathematical (and collegial, cordial) conversation going on, but to move chat threads when they become contentious or go off the topic rails. I tend to agree with the idea that MO is somewhat sui generis among SE sites, and not all the "usual SE rules" need be followed to the letter. $\endgroup$
    – Todd Trimble Mod
    Commented May 6, 2021 at 16:31
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    $\begingroup$ Todd's comment seems great, and my earlier comment isn't intended to disagree with it. I think the previous moderator practice of occasionally using this tool in the situations Todd outlines is great. (Essentially I see it as situations where those comments should probably be deleted, but it's more transparent to just move them to chat, since deleted comments aren't even visible to high rep users.) $\endgroup$ Commented May 7, 2021 at 15:31
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    $\begingroup$ @ToddTrimble Shouldn't you post your comment as an answer? Just in case somebody deletes it or moves it to chat. :-) (Just pointing out the irony. Seeing that the most upvoted answer refers to your comment, it was difficult to resist.) To include also some useful content in this comment, I will add a link to the Wiktionary entry for sui generis - I guess there might be some users (like me) for whom this might be helpful. $\endgroup$ Commented May 8, 2021 at 5:01
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    $\begingroup$ @FedericoPoloni I'm not a moderator but I think participants can provide their opinion too: I'd most likely view it as a "stubborn way to go against the opinion of the community". By the way, "incorporating the contents" can imply some improvements, or the contrary, adding errors, etc, omitting some crucial point, not insisting on the main point, etc. It most likely omits the date/time of posting the comment, which is a piece of information. $\endgroup$
    – YCor
    Commented May 10, 2021 at 6:47
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    $\begingroup$ @FedericoPoloni That's never happened as far as I can remember, but someone incorporating comments into a (CW) answer is itself not likely to be unwelcome. How the flag is handled would be on a case-by-case basis. I don't think I can give a blanket answer that would cover all cases. "Hard cases make bad law." $\endgroup$
    – Todd Trimble Mod
    Commented May 11, 2021 at 0:35
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    $\begingroup$ @FedericoPoloni Yes, indeed, that has happened. But I can't recall a case where someone both assembled a bunch of comments into an answer and flagged to have comments removed. $\endgroup$
    – Todd Trimble Mod
    Commented May 11, 2021 at 10:20
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    $\begingroup$ @Dima, "deletion of comments by moderators" is ambiguous. If you don't like "deletion by moderators of comments," how about "moderators deleting comments"? Or maybe a couple of commas would work, "deletions, by moderators, of comments"? $\endgroup$ Commented May 13, 2021 at 23:44
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    $\begingroup$ @bathalf15320 As a non-native I'm pretty sure I corrected many natives (writing such things as "would of", or "it's" in lieu of "its"...) and also any editor here is not supposed to know who's native and who's not. I've also asked natives about precise points, with distinct answers. As regards the title, I think both options are grammatically correct, but I'm not that sure. This digression might deserve deletion by moderators at some point :) $\endgroup$
    – YCor
    Commented May 14, 2021 at 10:42
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    $\begingroup$ I have to say that I am also a bit surprised to see that this post was manually removed from the Hot Meta Posts. Previously I only found one such instance on this meta - in that case it seemed warranted. (It was the nomination thread and it happened at the time when the nomination phase of the election was over.) $\endgroup$ Commented May 15, 2021 at 4:37
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    $\begingroup$ @YCor "deletion by moderators of comments" means: "deletion (of implicitly understood something) by moderators of comments". Surely that's not what you meant. OK, I should apologize for dwelling on this. $\endgroup$ Commented May 15, 2021 at 8:53

4 Answers 4


Vote up this answer if you think the instrument of moving a comment thread to chat should be used along the lines of Todd Trimble's comment -- i.e. only if a discussion in comments goes off-topic or becomes contentious. (Vote down if you don't think so, and leave alone if you don't care.)

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    $\begingroup$ I voted up this one, but conditionally not to have a broader interpretation of "goes off-topic" than Todd Trimble's practice. $\endgroup$
    – YCor
    Commented May 8, 2021 at 5:05
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    $\begingroup$ I think it's hard to talk maths in chat, as it does not typeset maths, so one is left with dollar signs etc all over the place. $\endgroup$ Commented May 13, 2021 at 22:08
  • $\begingroup$ @Dima testing $\pi^e$... $\endgroup$
    – David Roberts Mod
    Commented May 13, 2021 at 22:59
  • $\begingroup$ well, point me at a chat that had proper maths typesetting. my experience is that it doesn't work. $\endgroup$ Commented May 14, 2021 at 6:33
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    $\begingroup$ @DimaPasechnik Related older topics: MathJax on Chat and What's the point of having an *MO* chat without LaTeX enabled?. $\endgroup$ Commented May 14, 2021 at 23:15
  • $\begingroup$ these are not working on a setup I tried - these are probably too tied up to a particular browser. $\endgroup$ Commented May 15, 2021 at 8:45
  • $\begingroup$ Has anyone tried to ask upstream, i.e. Stackoverflow folks, to enable MathJax in chats? $\endgroup$ Commented May 15, 2021 at 8:46
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    $\begingroup$ @DimaPasechnik You mean feature requests such as Why is there no support for MathJax in chat? on Mathematics Meta or Any chance of MathJax in chat? on Meta Stack Exchange? $\endgroup$ Commented May 15, 2021 at 9:05
  • $\begingroup$ as far as I tried, no way to get it working on an Android phone. $\endgroup$ Commented May 15, 2021 at 10:16
  • $\begingroup$ In case somebody stumbles upon the above comments, here is continuation of the above conversation in chat. $\endgroup$ Commented May 16, 2021 at 2:22
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    $\begingroup$ As I just found while trying to follow up on a math discussion that has been moved to chat, another misfeature (apart from lack of MathJax) is that chat room are automatically frozen after as few as 14 days of inactivity. $\endgroup$ Commented May 16, 2021 at 7:31
  • $\begingroup$ I'd like to correct myself on MathJax support - it works on Android phones (we had a long chat with the author, involving creation of videos to show the problem etc etc), but it is rather inconvenient there, as bookmarklets don't work as usual, one basically has to search for a stored bookmarklet by using the URL window of the browser, and execute it. Also, creating this (not quite) bookmarklet involves editing the bookmark body and pasting raw JavaScript code there. $\endgroup$ Commented May 16, 2021 at 8:56
  • $\begingroup$ The old instructions on the bookmarklet made it totally unclear, but now they're amended to alert Android users. $\endgroup$ Commented May 16, 2021 at 8:57
  • $\begingroup$ even user-facing Google employees thought that bookmarklets don't work on Android at all :-) paul.kinlan.me/use-bookmarklets-on-chrome-on-android $\endgroup$ Commented May 16, 2021 at 9:01
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    $\begingroup$ @EmilJeĊ™ábek I will add to your comment that frozen rooms can also be unfrozen by moderators, if they are needed again. (Not necessarily MO mods - a moderator from any Stack Exchange site will do. But I suppose that this happens rarely for rooms moved from the comments.) My comment is mostly for the benefit of other users reading this - most likely you already know about this. $\endgroup$ Commented May 16, 2021 at 12:26

Vote up this answer if you think the instrument of moving a comment thread to chat should never be used at all. (Vote down if you don't think so, and leave alone if you don't care.)


As I have pointed out some time ago, if people want to contribute mathematical content, they should post an answer, not comments.

In this specific case, @Nate Eldredge and @Michael Greinecker should have posted their content in answers.

Comments are (1) ephemeral and meant to be deleted, and (2) should be used mainly to suggest improvements to the question, not answers or partial answers. The moderators did nothing wrong if they removed them or moved them to the chat, because they were not supposed to be there in the first place. SE is working as intended here; users just need to stop using it in the wrong way. :)

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    $\begingroup$ Maybe this should be a comment, not an answer? :-) $\endgroup$
    – Lucia
    Commented May 5, 2021 at 22:15
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    $\begingroup$ Why should we care about the stackexchange model? MO has always used comments in a more free-wheeling way. $\endgroup$ Commented May 6, 2021 at 13:54
  • $\begingroup$ @Andy From my point of view, because it works well. Why not using a traditional forum, or a usenet group, or a mailing list instead? All of them have been tried, as far as I understand, but (by chance or by merit) MO is the one that has the largest online community of mathematicians today. (Anyhow, from a more practical point of view, in the linked meta thread I listed various drawbacks of writing answers in comments). $\endgroup$ Commented May 6, 2021 at 16:02
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    $\begingroup$ It is the largest community, but not because it slavishly insists on following the "stackexchange model". We use their software, but our culture and practices have always been an outlier on their network. $\endgroup$ Commented May 6, 2021 at 16:19
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    $\begingroup$ Hi Federico: Unlike other parts of StackExchange, I view MO as a community of colleagues. From that point of view, I'd very much prefer this to be informal and respectful. For example, it wouldn't occur to me to tell my colleagues what they should do (and they probably wouldn't listen anyway!). $\endgroup$
    – Lucia
    Commented May 6, 2021 at 17:40

Vote up this answer if you think the instrument of moving a comment thread to chat should be used along the lines of SE's intentions -- i.e. to move longer discussions in the comments to chat as a more suitable venue. (Vote down if you don't think so, and leave alone if you don't care.)


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