Priority date 2007, I'd be surprised if there wasn't any prior art by that date. I know I was working on a P2P streaming system in 2006, for example.

There are many p2p networks for streaming content - they seem to be popular in Asia for watching English and European football, and I think many of these existed prior to 2007.

I'm sure there's a mountain of other prior art covering the concept. It isn't novel to anybody with half a brain. I was streaming audio in the 90s and clearly remember thinking about a p2p network then, because of the expense and legal threats I was receiving. All I wanted to do was enable football fans living abroad to listen to the local radio station on match days.. I thought I was doing the BBC a favour by extending their broadcast range! Yeah, I was just a naive kid. :)

PeerCast.org comes to mind. April 2002. IIRC it was based on Gnutella.

I would not worry about this patent. There is prior art.

For instance, this paper I wrote in 2002 uses techniques which overlap with their claims: http://www.springerlink.com/content/ujrmkgp929v6je7p/