I don't know if this is the appropriate forum, but I'm not a coder and the thread seemed right. My apologizes if the mod feels a need to move it. I wanted to toss out an idea for anominity so that others with more skill could contemplate if it was practical, feasible, too bandwidth consuming, or whatever:

1st, when a file query is received, the receiver never, ever looks at the content of its own hard drive. Instead it queries only its immediate neighbors. Call it a temporary subnet. If the neighbor replies yes it has the file, then rather than connect the requester to the content provider, the middle computer acts as a NAT router to pass the file, but never reveals to the requester the IP addy of the source. If the immediate neighbors all say "No," then the request is passed along to one of the immediate neighbors, a new temp subnet is formed with its neighbors, and the process repeats. And since one of the immediate neighbors is the one that referred it, the hard drive that was originally skipped will get checked as well. Its kind of a mutual denied culpability. Infinately slow? Bandwidth hog? TTL failure ridden? I have no idea. But anyone who asked for a file could potentially receive it. And they'd never know from whence it came.