Additional specs/protocols to consider/look at/have handy for reference:
10. Activity Streams (atom on steroids) http://activitystrea.ms/
11. OpenID Connect http://openidconnect.com/
12. Oauth 2.0 (This is a new spec) http://hueniverse.com/2010/05/introducing-oauth-2-0/
13. PoCo (portable contacts) http://portablecontacts.net/
14. XAuth (discovery) http://xauth.org/
15. WebFinger (discovery) http://webfinger.org/ http://code.google.com/p/webfinger/
16. Salmon (defining scope of decentralized publication) http://www.salmon-protocol.org/ http://code.google.com/p/salmon-protocol/
17. PubSubHubbub (centralizing portability feeds via push notification) http://code.google.com/p/pubsubhubbub/ http://www.youtube.com/watch?v=B5kHx0rGkec
18. XMPP, XRD, & JRD (the evolution of a connectivity backbone) http://hueniverse.com/2010/05/jrd-the-other-resource-descriptor/
19. The Internet Identity Workshop http://www.internetidentityworkshop.com/
To learn more about the distributed social semantic web space, see my article, A Flock of Twitters: Decentralized Semantic Microblogging
A great slide presentation on the Social Web by John Breslin and Alex Passant (see slide 68-69 for some specific motivation): The Social Semantic Web
Interesting new idea, the Semantic Pingback.
Here’s a WordPress plugin that creates a PubSubHubBub hub in your WP install. This could be one key piece in helping to make WordPress a truly distributed platform.
http://wordpress.org/extend/plugins/pushpress/
An article on how FOAF+SSL allows the creation of a Web of Trust (WOT) without the need of key signing parties: http://blogs.sun.com/bblfish/entry/more_on_authorization_in_foaf