Chatroulette may be a fad and it may be more - only time will tell.
I've seen two videos that show some interesting aspects of communication revealed by Chatroulette. In the first one, pointed to by Gruber here, the documentary maker explains Chatroulette and discovers that partners mostly stick around for pretty women:
In this one a musician is able to keep partners by entertaining them:
Both videos show that you can keep viewers by engaging them. It is remarkable that there is such a low barrier to this kind of research. Testing a cleaver idea takes no money, only an idea and time. It is also remarkable that so many people are sitting around waiting to be entertained.