Facebook co-opting twitter?

Woah, facebook is now using a @ notation that Twitter is using. Maybe they've been doing this for a while, but it's the first that I've seen it so far.

So now how does this work, does it let me link my Twitter account and my friends' twitter accounts to their Facebook or can I use @ and it will still get to them.

I suppose I should look up how this works, a shame that their UI doesn't give me a link to learn more.

Although an interesting point, if it is actually linked up to Twitter, how come it's giving me this note, my Twitter account and Facebook accounts are separate unless ... Data Mining?