That wasnt someone yelling "you rock",  that was a U.S. Marine yelling "Ooo Rah". It's a military thing that's done/yelled as a sign of approval. Each branch has their own version, in the Army it's "Hoo Ahh" like Al in Scent of a Women. Can't beleive you thought it was "you rock".  Your not knowing that what this was is a perfect example of how most people are so removed from this war and the vets that are fighting it.  Sad.