The site is named after the engineer who started it (apparently he has been obsessed with this stuff for a while, including starting social networking projects for Stanford alumni), and is not officially part of Google’s product portfolio yet, according to Google spokesfolk, though Google owns the technology.
One Google employee comments on it here.
News.com piece.
Search Engine Watch’s coverage.
Update: By the way, the unique thing in this system, far as I can tell, is that the only way you can get in is to be invited by someone who is already in. And the first folks in were at Google. That in itself is an interesting plotline.