Which users can be referred using @ followed by the username?
The users that can be notified using a @-reference are:
- In questions
- any user who edited the question
- the moderator who closed the question
- any commenter who wrote a comment for the same question
- In answers
- any user who edited the answer
- any commenter who wrote a comment for the same answer
Are there users that are automatically notified of a comment?
The users who are automatically notified of a new comment are:
- the author of the post
- in the case of comments between two users, the user who wrote the previous comment
- if a user comments on their own post and there is only one person who has previously commented, then that person is also notified if @name is forgotten
How do I notify a user with a username containing spaces?
When the user name contains spaces, to get the user notified the username needs to be written without any spaces. This means, for example, that a user using this is a name with spaces as username will be notified with @thisisanamewithspaces.
Any single punctuation character following the name is ignored. This means that the following comments will notify name.
@name: This is a comment.
@name, This is a comment.
@name. This is a comment.
[Reference: This question on Meta Stack Overflow.]