They just post videos/songs/albums from up and coming bands. I haven't found one yet that I didn't think was at least moderately awesome. Just start clicking around. I think it's a really cool idea and a place for musicians that maybe aren't quite at their peak to get a fanbase. August Moon is pretty cool, as is Mountain Asleep. Thousandaires are pretty cool if a little cheesy.
RIYL: Daytrotter, but more punk and mathy.