WordPress
The majority of these plugins are concepts that could be built as plugins for the wp-openid plugin.
- wp-openid-profiles - profile-subscription extension for wp-openid.
- wp-openid-avatars - takes the logo/photo propery of hcard and pushes it around your blog -- into your comments and so on and adds support for uploading your own custom avatars for users, importing them from Gravatar, Flickr, MyBlogLog and elsewhere.
- wp-openid-delegation - Besides doing the standard XRDS/YADIS delegation, this plugin would also handle rel-me linking throughout a site, including on people's profiles (see wp-openid-profiles) - http://willnorris.com/projects/wp-yadis
- wp-openid-contactform - http://factoryjoe.pbwiki.com/wp-openid-contactform
(adapted/trimmed from http://factoryjoe.pbwiki.com/DecentralizedSocialNetwork)
More:
- wp-openid-whitelist - use XFN rel values linked with openids to whitelist commenters.
I've written an XRDS plugin for WP -- while the interface is lacking, the backend is all there -- what's great is it focuses not only on OpenID (although I use it primarily for that) but also on any other XRDS based protocols (such as my Pempeth<http://singpolyma.net/pempeth/>) -- it allows for services to be added by both users and other plugins (ie, if the plugins themselves provide an XRDS based service).
My 'friend bookmarklet' plugin <http://singpolyma.net/plugins/friend-bookmarklet/> is an experiment in giving users an easy way to add contacts to their WP blogroll.