That's a decent analogy. I remember all my friends almost simultaneously dumping Myspace for Facebook fairly quickly once they perceived the crowd's momentum in that direction. Now, no one I know uses Myspace, except to post band updates that I doubt anyone reads anyway (that all I ever used it for to begin with, what an ugly place that was!).

Facebook seems to be keeping 'hot' so far, amazingly enough, although there are 'elite' crowds forming at Twitter and the other places. Of course, I think that unlike bars, the people on a service can actually serve to keep each other there. Why go to Twitter if all my friends use Facebook? I might be elite, but I'd be all alone.

Dancing with myself, oh oh... ;)