@ - followed by a member's username - is intended as a way to "notify" that user that they've been mentioned in a forum post, only I haven't had that turned all the way on before. So, when someone has typed something like @msg-commander, the name gets highlighted and becomes a clickable link to my profile page, but I don't get any notification about it.
Note that you have to type the username, not the display name.
If you type @MSG Commander, for example, it won't work. It has to be the member's username (which may not always match their display name).
I've gone ahead and added everyone's @ username in the forum. It only shows up when you're logged in though... If I did everything else right, it's also set up now so that the member you mention, will get an email notification.
If you don't want email notifications, you can turn it off on your profile page. (Details in a bit)
Along with @ mentions, I've also turned on "Friends" just for the heck of it. So now if you want to, you can make friends with other members...
Additionally, turning on the @ mentions automatically creates a user "Activity" stream on each member's profile page (it's all bundled together). The activity stream is kind of like a miniature Facebook wall - you can post on your own, and I believe, you can post on other people's. Though it's totally optional, and also experimental - if the database gets overloaded and/or the site becomes super slow I might have to turn it back off.
Anyway, you can decide whether you want email notifications for all this stuff by navigating to your profile page, then clicking Settings -> Email.
A lot of stuff, just to properly enable @ mentions - but hopefully it all works, and adds to your overall enjoyment of the site.
