I would not consider that a problem, since a ranking could contain more than one host. But I believe that the algorithm for host caches should be improved. LimeWire currently saves 400 Ultrapeers, 100 normal peers and about 20 local IP-adresses in a hosts file, which is not really highly optimized.

Concerning encrypting documents: I really think authentification would be better. If some files would require some kind of authentification handshake to make the connection, you could control who downloads the file. Instead of encrypting private messages, you should use PGP and eMail ;-). But I don't want authentification implemented in clients (people could start using it).

Btw. Talking about messages, I thought of a way to use Gnutella as underlying protocol for a decentralized forum. Would you think that could be useful?

Asking somebody to commit a crime is a crime, too, in Germany. When I ask somebody to kill a person, and he actually does that, I could be found guilty, too. I thought that was common, - it is common at least in Europe. I also believe, that's the right way to handle that. But anyways I was actually talking about the police agents, who are not allowed to ask (undercover) a supposed criminal to commit a crime.