I seem to be running into a problem when attempting to reply to a comment from a user whose user name has a space in it. When I use the @ symbol and begin typing the username, the name will appear is a small popup which I can then click and it will be entered into the comment.

However if the name has spaces then the username in the popup as well as the user name automatically inserted into the comment does not have spaces.

The result is that the username that is automatically inserted into the comment is incorrect.

For instance in my response to a comment to an answer I provided, https://raspberrypi.stackexchange.com/a/77672/73672 , it appears that I need to add a space to the name from the popup and when I do the user is notified via their global mailbox.

2 Answers 2


it's not really something to be worried about, the purpose of using @username is so your message appears in their inbox.

This answer on Meta StackExchange covers the topic really well. But to answer your question spaces are automatically taken out of the username when you use @username to mention someone in a comment. From the Meta post:

Spaces are removed from the display names for matching purposes. So to match Peter Smith you may use @pet, @peter, @peters, or @petersmith. The last two are useful if Peter Jones is also participating, who can then be distinguished using @peterj. However, no spaces are allowed in the @name itself. Like to notify P Smith, one must use @psm or @psmith. (Here @P Smith would be handled as just @P, which is too short.) Single quotes, dots, dashes and underscores should not be removed.

  • This explanation does not seem to match up with the actual behavior of the @ symbol. I am modifying the name that shows in the popup by entering the missing space in the comments to my answer raspberrypi.stackexchange.com/a/77672/73672 and that user is responding to my comments so they must be receiving notifications. Mar 8, 2018 at 11:45
  • 1
    If you post a comment and someone follows it with another comment, generally you will receive a notification regardless of whether they addressed you with @ or not ("generally" because I think there are some qualifications to that, e.g., how many comments in total there are and how many are yours, etc.). In any case, if you feel there is something wrong with the functionality of a feature, the place to take it up is the master Meta SE site: meta.stackexchange.com The mods here are not employees and are not involved in programming the site, all we can do is provide information.
    – goldilocks Mod
    Mar 8, 2018 at 12:39
  • @Richard, as long as your ping contains more than 3 letters and is unambiguous, it will work (even @ksh would be sufficient in your example). That matches with what is mentioned in the quote; putting the space in just means your ping is parsed as @Kshitij, which meets the criteria. As goldilocks indicates, more comprehensive documentation is available on Meta Stack Exchange at How do comment @replies work?
    – Aurora0001
    Mar 8, 2018 at 20:13
  • @goldilocks thanks for the note about site functionality being for meta.stackexchange as I was under the impression that each site had its own meta. There do seem to be differences in the look and feel of different sites though that may just be a easily changed skin thing. I re-read the How do comment `@replies work and I think I misunderstood that as well. A comment to a comment of mine some time ago implied that the space was necessary for a user to get the notification so that is why for the comment exchange on the post of my question that I thought the space necessary. Mar 8, 2018 at 20:27

something else that I noticed is that often people will have a space in their display name, but their user name (which is often similar) will not have the spaces and could be very different.

For example, Richard Chambers who responded has a user name of @richard-chambers, but the display name is just 'Richard Chambers'.

The Displayed Username can have spaces, but the actual username cannot have spaces. When you see a name, highlighted in that orange link, its actually their display name and not the username. It can be deceiving because the "tag" / "author" / "commentator" line is smart enough to do that translation, but when you type it in the body of a comment, answer or question, you have to do the actual username (not what is displayed) with the 'at' sign.

  • Stack Exchange doesn't actually have a concept of 'usernames'. Your unique identifier is your user ID used by the system, and you then have a display name which humans use (e.g. your user ID is 24619 and your display name is 'Keith E. Truesdell'). You don't have any other username; the bit you see if you go to someone else's profile URL is just your display name with spaces converted to dashes. Fun fact: try changing the last bit of your profile, like raspberrypi.meta.stackexchange.com/users/58316/not-aurora - notice that it still works if I use another name that isn't my display name.
    – Aurora0001
    Mar 20, 2018 at 20:08

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .