Of course you must already have heard of The Onion Router project called Tor.
A particularly neat feature is its hidden services, not so much for trying to be hidden (which papers have proven to fail… they can easily be located with a confirmation attack) but for the fact that onion address provide better cryptographic authenticity proof than HTTPS.
How is this related to PSYC?
Tor support in psyced
There's also code for active connections to onion psyc nodes, thus leading into a Tor-based kind of federation – but it doesn't work yet.
PSYC2 would love to use Tor, but…
Tor by design provides good scalability for client/server and federation architectures but in the absence of a pubsub and multicast implementation has terrible scalability properties for social and distributed applications such as secushare.
It may however remain interesting to enhance anonymity in the way the GNUnet network is reached by passing through Tor first, whenever a client/server kind of architecture is not a problem. This, and generally the problems of doing social networking on top of Tor, has been discussed in-depth in a thread on the tor-talk mailing list starting in December 2014 thru January 2015.