Platforms to consider

Please include status for each.

OneClimate (site). Not open source or with open protocols, but have expressed an intention to work with the Coalition model, i.e. interoperability. Watch this space. Status: Site is operational; no interoperability yet?
Upcoming open source social networks, alternatives to Facebook:Status:Diaspora – high profile, but some controversy and grumbling about the developers’ methods and openness among the open source community. Status: operational (early Beta)
Friendika[1] – current reports (end Nov 2010) suggest it’s more stable, and with more features than Diaspora, including implementation of OStatus (with some variation); but less polished-looking (minor problem). Status: operational (Beta?)
Open CoopProposed PlaNet social network Status: ?
GNU Social. Started by modifying StatusNet code; based on same protocols.[2]. Development seems to be stalling. Status: Early Beta. Stalled?
Appleseed the first open source, fully decentralized social networking software. Some reports of lower usability.
PanGaia: Aiming to be a complete solution for the virtual side of things. Check the “structure” page and note similarity to cotw video. Status: Pre-alpha; details and working package not yet available.