I remember thinking about a similar concept a few years back. It would be good to have a p2p archive of human knowledge for end of the world scenarios.

The problem is Bittorrent isn't the protocol for it, it doesn't allow incremental changes. You also don't want the complete history like git, you want something that passes a diff around.

It would be great to have a p2p network with Wikipedia, a load of academic papers, maps and recipes, which anybody with a computer could contribute drive space to storing.