P2P overlay networks since 2001?

Question

What has been happening with the four big P2P distributed hash table (DHT) overlay networks — Pastry, CAN, Chord, and Tapestry — since they all came out in 2001?

I know that academic projects continued for a few years, and sporadic maintenance releases still appear for some of them, but did any ever end up in major-scale, non-academic use? Is there still an active dev community around any of them?

I've take a few journeys through Google and Wikipedia, but there's no real information about what has happened recently, and their web sites are all moribund.

Update: I see that Chimera (the successor to Tapestry) is still under active development, with recent research publications: http://current.cs.ucsb.edu/projects/chimera/index.html

Update #2: given someone's -1 for the question, I should be more clear about the programming side - I'm interested in a general-purpose P2P overlay-network library and associated standards that would make a firm foundation for a P2P social networking app. All the existing ones I've looked at, including Chimera, seem too weakly-developed and supported and/or too out-of-date to form a solid infrastructure layer. I'd like to know what other options I have.

Update #3: Mainline DHT seems to generate a few questions here. It's based on Kademlia, and as far as I now, has specialized use mainly as a distributed search protocol for Bittorrent.

Answer 1

did any ever end up in major-scale, non-academic use?

DHT's were designed to solve a set of issues which were described in a theoretical/abstract way. In 2001, people did not know much about the practical aspect of P2P communication. Proper NAT traversal solutions were not available (or even understood correctly).

None of the DHT designs addressed the practical aspect of P2P communication (i.e., How do I actually contact another device over the Internet? How do I find it? How do I establish a connection to it? How do I deal with NATs, Proxies, public and private addresses? etc...).

Hence, there was not enough 'context' for them to thrive, which explains their current status. Today, all the pieces of the puzzle/solution are available, but no one has connected them in a unified framework.

I wish I had more time to finish the Chaupal project.