Platforms to consider

Websites and/or software that might meet the requirements to be part of the CN.

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.
Non-federated platforms – these could be pertinent if steps are made towards interoperability, allowing connections between each other and with other social network platforms:

Kopernik Connecting donors and needs around appropriate technology solutions worldwide.
Global Action Plan An ambitious, coordinated (multi-site) project in UK and worldwide.
WiserEarth (site and maybe software will be open sourced eventually). Status: Site is operational; no interoperability yet?
CrabGrass (demo) – more of an organizing tool than a social network, still in early stages, with work needed on usability.
BuddyPress (demo) – little control over activity stream means this seems more chatter-oriented, much less supportive of a clear focus, and therefore not suitable for vision-focused or task-oriented usage. This would need to change drastically before it could be useful for the task. Runs on WordPress.