Facebook versus MySpace

I’ve heard Facebook described as MySpace for adults. If that’s the case, why are the kids flocking to it, and will all the adults leave and go to MySpace? Does this behaviour remind you of a herd of bison? It does me. I wonder whether we’ll all continually move from one social networking site to another? If we do, what does that do for their business models? Or how long will it be before someone connects them all together?