This story isn't about P2P architecture, but it has much in common with file sharing - unauthorized access of someone else's content.

Slate has a fun feature called Other People's Porn that lets reader in on a Dirty Little Cable Secret - when a local cable customer orders video on demand it's sent on an unencrypted digital cable channel to a node (some 400+ homes) and not specifically to one cable box, and so can be accessed by others.

Viewing other people's video is a potluck experience. There are various caveats that can make it an entertainment choice of last resort. You need to have a QAM (Quadrature Amplitude Modulation) tuner. You have to hunt for the channels to see if anyone is watching anything interesting. And you're at the whim of the other viewer who may pause, fast forward, or quit the program.