A menu selection spotted during a demo of Unreal Tournament 3 seems to suggest that Sony is working on a player-identification system, perhaps similar to Xbox Live's Gamertag. After seeing the "Gamercard" option in a menu at the Edinburgh Interactive Festival, Games Digest was reportedly told by Epic's Mark Rein "Oops, you shouldn't have seen that."
What's more, a member of the Evil Avatar forums put forth an image from PlayStation Home that also has the "gamer card" option, this time with a space in the middle. We know very little at this point, but thought you all would appreciate a head-start on speculation. By the way, if the phrase "gamer card" seems familiar to you, you aren't imagining things.