It appears the feature is live for everyone. To try it, just go to a friend’s posted item in your news feed, click “share,” and you’ll see a “via [your friend’s name]” (with an option to remove it). Once shared, the item will appear on your profile, with a via link that points to your friend’s profile. Your friends will also see the item in their News Feeds, creating the viral loop that is the Twitter retweet.
Currently, the feature only works for posted links – you can’t “via” someone else’s status update or photo. Nonetheless, given the most visible use of retweets on Twitter is links, with aggregators like Tweetmeme tracking which stories get retweeted the most, it’s a big move for Facebook that makes its service even more Twitter-like.
Where the feature goes from here, we’re not sure, but given the social network’s ambition to make more and more of what you post public, it’s clearly another attempt to become more relevant in the world of real-time news, search, and information. Whether or not users respond and start posting “shared via links” (is that what we call them?) will also remain to be seen.