At one point, putting "@" before a username wasn't a well-known way to reach out to someone. But Twitter's made that action a bit more commonplace. As many on Twitter know, by putting "@" before a username allows the sender to reach out to others on Twitter. Today, socialmedian, a second-generation social news site, released Replize, a feature that extends the "@username" function. (Here's a video of Jason's pitch on what socialmedian is).

Here’s how the new Replize feature, according to socialmedian.

1. To send a replize to any user on socialmedian, all a user needs to do is include @username for any username(s) anywhere in the comments field.  If you click the “reply” link next to a comment we’ll pre-populate the other person’s @username.  You can include several people in a replize, e.g. @jasongoldberg @louisgray @nishith.  The replize will be sent to all.
2. We then highlight the replize to those users in their homepage News Feed.  Users can also be notified by email whenever they have a replize.
3. We’ve also added a “Replize” tab to the homepage so that users can easily view all their replize in one place, and thus quickly see all the stories they have been included in discussion