If you haven't checked out YouBama yet, you should.
Created by two Stanford University students, it's a very smart use of social media to build, and grow, a platform of grassroots support.
Mashing-up both YouTube and Digg, all of the content on the site is both created and ranked by viewers such the the most popular videos rise to the top.
As you will see, it's a simple, yet effective presentation that doesn't try to be more than what it is. And this is why it works so well.