I've used them before. I ran a Squid proxy and connected it to the NLANR cache hierarchy[1]; despite the name, it's more of a mesh with siblings. For the best s

I've used them before. I ran a Squid proxy and connected it to the NLANR cache hierarchy[1]; despite the name, it's more of a mesh with siblings. For the best speed, you can use bloom filters (or cache digests, in their terms[2]) to avoid the extra latency of a request of "hey, do you have this URL cached?" from someone who definitely doesn't. [1] http://wiki.squid-cache.org/Features/CacheHierarchy http://wiki.squid-cache.org/Features/CacheHierarchy [2] http://wiki.squid-cache.org/SquidFaq/CacheDigests http://wiki.squid-cache.org/SquidFaq/CacheDigests