http://www.cl.cam.ac.uk/~ph315/
"A Socio-Aware Overlay for Publish/Subscribe Communication in Delay Tolerant
Networks" and others.
http://www.cl.cam.ac.uk/research/srg/netos/haggle/ (many broken links, the
researcher promised he'd fix them soon).
Might be interesting; long term IMHO Freenet is going to have to use this sort
of stuff for a lot of traffic in more hostile environments: If the
authorities implement traffic flow analysis on the internet, you have to use
non-internet transports, which means wireless, PDA rendezvous, sneakernet,
and the occasional parasitic internet transport (e.g. steal the video stream
on skype). But the papers may be interesting even in the nearer term;
community detection (like robert's network coloring code?), social
networks ...
Caveat: I haven't read the papers, I don't have time right now.