Sound a little familiar? Well, it should - it's basically a machine-readable version of an LJ userinfo page. You describe yourself, and then link to people you know.
http://xmlns.com/foaf/0.1/ (the spec)
http://www-106.ibm.com/developerworks/xml/library/x-foaf.html (an intro article)
http://www.ldodds.com/foaf/foaf-a-matic.html (a foaf generator)