Napster wasn't decentralized, it relied on a centralized index which is why it was shut down. Gnutella relied on a broadcast search which didn't scale. Freenet's use of small world routing to be both decentralized and scalable was unique, as was it's use of cryptographic contracts (signed subspace keys).
That paper isn't the original Freenet paper, it came later. This is the original: https://www.semanticscholar.org/paper/A-Distributed-Decentra...
