So I understand that putting @username in a comment gives that user a notification of the comment. But I'd like some more specifics on this. Does using a partial name work? If so, which partial portion of the name (begining, middle, end)? Does the person have to have commented on the thread to get the notification? Does it work in answers or questions as well as comments?
It only works in comments against those who have posted comments on the same post and against those who have edited that post (the poster of the question/answer gets notified anyway).
You must use at least the first three letters (case-insensitive) of thier user name, and it matches the first relevant person in reverse cronological order of their comments.