What's your opinion about the new video distribution based on P2P of Wikipedia?
http://techblog.wikimedia.org/2010/09/video-labs-p2p-next-community-cdn-for-video-distribution/
I think it will be a big revolution in the net. Think about the application of this kind of approach to social network: why I need to store my photos on a private company server if I can keep them on my computer (and some replicas spread over my friend computer) and share them in a easy way? With good protocols, distributed file system, and of course software we can build an Internet 2.0, where not only the content but also the infractructure (badwidth, storage, cpu) are given by users.