http://tttyx2vwp7ihml3vkhywwcizv6nbwrikpgeciy3qrow7l7muak2pnhad.onion/Publications.html
The connections are bidirectional, near real-time, and can
be used for both connection-based and connectionless traffic. Onion
Routing interfaces with off the shelf software and systems through
specialized proxies, making it easy to integrate into existing
systems. Prototypes have been running since July 1997.