mediaor as a social network?

So, I was digging back into Ning tonight and wanted to see what I could do to turn my read-only Music 2.0 aggegrator into more of a destination using Ning's social network-in-a-box offering. I threw this together in about 20 minutes. I'd be interested in what you guys think.... is the social network angle more or less interesting than the "river of news" angle (built on Tumblr)?