When we started talking to people about the project, we'd often find that some didn't get how p2p works.  Not that you have to understand it to use it, but if you do want to, we produced a couple of simple animations (thanks Stu!) that explain how p2p works.  (Here, I mean p2p as in peer-to-peer software and not p2p as a philosophy, though there are obvious parallels!.)

Streaming