Open-source social networking platform

Wouldn’t it be nice to be able to use social networking systems without being locked into one platform and bombarded with adverts? I sure think so – I might actually bother maintaining a social network profile in that situation, and get back all the friends I’ve lost through refusing to use MySpace. So I’m pinning some hopes on the success of the Appleseed Project, “an effort to create open source Social Networking software that is based on a distributed model.” [Warren Ellis, again]