I was reading this article on CNET about an alleged class divide, and therefore race divide, between Facebook and MySpace users. I find the "study" a little absurd. Granted, I'm a sample of one, but my Facebook "friends" exactly coincide the race/gender mix that I know in real life, so I don't see any divide there.
What I do see is that people with an edgamacation and desire for some kind of order and control prefer Facebook, not for any social divide, but because MySpace is a steaming pile of shit-chaos. That's not a new development. MySpace has always sucked like that. The only reason it got out to a somewhat stronger start is because Facebook was a little slow to open up to the public at large and shed its college roots.
The bottom line is that I don't see a racial connection, I see a one site sucks really bad connection and people move on from it.