In answers, when people refer to other users they put a "@" before the username, like "@someuser said this and that". What's the function of the "@"? Is it to make clear to the reader that it's a username? Or for a script so that it can convert it to a link to the user's profile (future enhancement)? In that case, what about duplicate names?
Do I have to use the "@"? If so, do I have to concatenate names with spaces in them: @FedericoRusso?