One interesting trend I've been watching over the last year or so is the intersection of social and personalization as a way to discover new videos. And, of course, how it helps users to discover new music videos. The latest entrant into the social music video discovery category is Rockify, which just launched its public-facing portal for music videos, Rockify.TV, in public beta. Rockify.TV is kind of like Pandora for music videos, but with social hooks to help users find interesting content based on their own musical preferences, and those of friends.