Sam Ruby unveiled site.  It's still in beta, but it looks pretty good already.  RSS should have a site like that.  At the moment, I don't have anything Atom-enabled so I didn't add to the Atom-enabled directory.

Hmm.  Is it just my imagination or is there is a strong invisible presence of Joi-centered social network behind Atom?  There is nothing wrong with it, of course.  I am just amazed at how knowing the same person can create synergy.  I don't think such effect is limited only to powerbrokers like Joi either because the effect doesn't require the 'center' to coordinate or even be aware of the synergy he or she creates.  Such passive effects of social networks are much more powerful than the kind of forced activities encouraged by services like Friendster and LinkedIn IMHO.

Of course, there are negative effects which are just as interesting.  For example, put two people like Dave and Mark together in a social network and something sour happens.  I don't get along very well with Mark either.  While I don't think my friendship with Dave has anything to do with it, the subconscious mind is called that for a good reason.  I should do some reading on group psychology.

More I think about the magic of social networks, more I am fascinated by the human angle of it.