If you don't know what it is, then you apparently aren't.

Anyway, thefacebook is a online directory for college students that was started last year. Seems to be a profitable business, too. They've bought a couple of domain names, and are currently expanding into a high-school version.

Must be making more than I'd have thought off of those banner ads...

It is only open to American schools right now, I think. I could be wrong. Anyway, it seems to be almost as popular as AIM here at the University of Kentucky.

Yep, I'm on it. There seems to be a version for most British universities as well.