I would like to take better advantage of comment notifications. Where can I find a complete account of how they work?

For example, it appears that writing @FullUserName in a comment will lead to a comment notification alerting that user to the comment. Is it necessary to use the full user name? For example, if someone write @Joel in a thread in which I have already commented, will I be notified? Must I use the @ sign at all? (I find the @ sign to be an unnatural and disruptive element in the comments and would like to omit it whenever possible.) I guess we needn't use @ when making a comment on the person's own answer or question. Is the person asking the question automatically notified of comments on an answer to that question?

Recently, I noticed when writing a comment that if I start writing with, say, @Noah (I hope he won't mind if I use his username as a hypothetical example), then a little hovering overtext window displays a fuller username completion, e.g. NoahSynder (even though the actual user name of the user had a space: Noah Synder, so I find this window to be odd), but this window disappears when I put a comma, as in "@Noah, now I begin my comment", but also it becomes bold when I follow the completion, as in "@NoahSynder ", but the window disappears when the comma immediately follows the name, as in "@NoahSynder, ". What is the significance of these various fonts and missing spaces and disappearing windows? I guess that the first window was a suggested completion, and a bold name means a successfully recognized name, or what?

  • $\begingroup$ Do you mean Noah Snyder? $\endgroup$
    – JRN
    Jul 25, 2013 at 2:46
  • $\begingroup$ Oops, yes, I meant Noah Snyder. (Sorry, Noah). $\endgroup$ Jul 25, 2013 at 2:52
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    $\begingroup$ Those who want to play around might want to add a comment below addressed to "Joel" or variations of it, and we'll see who gets informed about it. :) $\endgroup$
    – JRN
    Jul 25, 2013 at 3:52
  • $\begingroup$ @Joel that's a good idea. I was notified of your comment. $\endgroup$ Jul 25, 2013 at 4:09
  • $\begingroup$ And I was notified of your comment above. $\endgroup$
    – JRN
    Jul 25, 2013 at 4:14
  • $\begingroup$ In general, a good place to look up features and how they work is the FAQ question on Meta Stack Exchange. $\endgroup$
    – Kaveh
    Jul 25, 2013 at 4:21
  • $\begingroup$ @Kaveh, that is a useful resource! (But in truth I find it odd to go to SO for answers about MO, since I don't otherwise participate there, and there is a different community and culture there.) I had looked for a FAQ here before asking my question, but somehow couldn't find it. $\endgroup$ Jul 25, 2013 at 4:33
  • $\begingroup$ I think it is in any case good such things do get asked here. In this way other users that might not even know about some feature have it drawn to their attention. Recently, I had an exchange on main with somebody that did not (yet) know about notification at all. $\endgroup$
    – user9072
    Jul 25, 2013 at 12:51

1 Answer 1


For full details see How do comment @replies work?.

Some quick remarks:

Space should be removed. The system tries to match what follows immeadiately after the @ until the first space (and one final punctuation is ignored) to a username with space removed. Part of the username also works. So @Joel is fine (except perhaps if there should be many Joels in the conversation) @Joel David Hamkins is the same as the system only looks until the first space (and ignores one interpunctuation-mark) thus @Joel, also works, but @Joel... not and @JoelDavidHamkins is what would be thecomplete version and what gets suggested.

For the window it is as you say it gives suggestions, you can type only part and select with 'tab' key to complete, if you select it becomes bold, exact match also makes bold as it is sort of autoselected. But you can also compltely ignore it. Just what is typed in the end is relevant, it is only an input-help (also see at the end).

That there is a fontchange is relevant as if there are still more than one match then there is more then one window and you can use 'tab' repeatedly to select one of them (the one selected is bold).

If you continue it dissapears as there is no more match @Joel, does not match part of your username but works as the interpunctuation is ignored, @Joel (with space) there is also no more window as you are ouside the scope of the @ after a space and so there is no reason to suggest anything anymore, but with @JoelD the window would still be there.

Also note that some people can sometimes be notified that do not get suggested, namely users that edited the post and moderators that closed a question.

Additional remark: in principle, the @ is crucial but as it always was the case a comment on a post notifies owner of a post. So here you do not need it. And also if there is a unique user that could be notified, say I had commented on you question and you replied in a comment with no others present, then I also get automatically notified even if you do not use an @ (whether you use my displayname or not). In such a situation it can happen that a staring @name is autodelete upon submission of the comment.

Second additional remark: no comments on answer do not automatically notify OP of question, you cannot even notify them via comments on the answer (except of course if they also commented there).

I hope this helps a bit, though I fear my reply is not very structured.

  • $\begingroup$ This is a good idea, I moved the link. In my experience in general meta.SO seems very good regarding most such things. $\endgroup$
    – user9072
    Jul 25, 2013 at 2:18
  • $\begingroup$ Thanks very much! $\endgroup$ Jul 25, 2013 at 2:19
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    $\begingroup$ There is one thing to add here: editors can be pinged, even when their username is not appearing in the auto-complete suggestions. $\endgroup$
    – Asaf Karagila Mod
    Jul 25, 2013 at 8:09
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    $\begingroup$ @AsafKaragila: either your addition is too subtle for me (in the sense that I do not understand what it adds while it does), or it is no addition. "Also note that some people can sometimes be notified that do not get suggested, namely users that edited the post and moderators that closed a question." $\endgroup$
    – user9072
    Jul 25, 2013 at 12:41
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    $\begingroup$ Or... I was just dreadfully tired all day and I missed that part in your answer! :-) $\endgroup$
    – Asaf Karagila Mod
    Jul 25, 2013 at 18:57

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