Plexus

Jun25'2009: Mark Pesce announced the launch of Plexus, an Open Source project building a P2P Open Social Networking Model.

http://blog.futurestreetconsulting.com/?p=381

http://plexus.relationalspace.org/

http://plexusdev.wikia.com

Using Python, at least for now.

Using JSON equivalents of MicroFormat-s for data interchange.