Two Hours of P2P: Why care about P2P?
There's a difference between neat stuff and significant stuff. Peer-to-Peer: Harnessing the Power of Disruptive Technologies does a great job of explaining how P2P works, all the way down to free riding and scalability.
But it fails to tell us why people outside of the technical world should really care. It raises many more questions than it answers. It fails to address the true social implications of technologies like this: do Harry and Martha in Dubuque need peer-to-peer?
Jon Katz, Slashdot, Does Peer-to-Peer Suck?