That's neat!
Actually, I don't think that would be a hard project to develop, all things considered. I'm sure that some of the other features that they have take more research/planning (like the "automatic buddy lists"), but those types of things would be asy to do).
I'm still very impressed by the whole system, it's neat!
I don't think my list will ever be accurate, though. I always leave WinAmp playing when I go to sleep/school, so it plays some music I don't like that much (unless I leave it on Exodus or something like that, since Newby gave my their discography... 9:00:00 or so of music).