We have a P2P file-sharing program that does this, called U-P2P (http://u-p2p.sf.net). Content is hashed, and you use a Gnutella search using the hash to retrieve it. Documents are organized by what we call "communities", which themselves are represented by a document and its corresponding hash. So the document name is really made up of two hashes: the one of the community it belongs to, and its own hash. You can use these hashes as hyperlinks, and U-P2P resolves it via search, as previously mentioned.

What we think is great about it is that the hash is location-independent. There could be multiple copies of the document at various locations at any given point. As long as there is at least one copy and that it is reachable via search, it will be retrieved.

We also built a distributed Wiki based on that idea and platform, called P2Pedia (http://p2pedia.sf.net).

It's all very much an academic research project, so don't expect a beautiful interface or easy-to-install packaging or anything, but I think it's a good proof of concept.

(note to self: we should really move these to GitHub).