I'm sure this idea isn't original. It's too obvious. In fact, I'd bet money that somebody is already doing it.
Consolidate the social networks. Write a nice abstract social network layer, and connect all the data into one large, meta, ...social internet.
Wired predicts that in 2007, if this doesn't happen, the social networks will start to die. People just can't keep up with all their different profiles, and having some connections here and others there.
It's a great spot to start a startup, so go forth and prosper! I'm too busy to do it, but if I was a poor student I'd be all over this. Maybe if you're smart enough I'll invest in you.