Friend-of-a-Friend (FOAF) is an XML and RDF application. FOAF allows the expression of personal information and relationships, and is a useful building block for creating information systems that support online communities in computer readable format.
By describing yourself using FOAF, you are providing information, in a machine-processable format, about yourself, your interests, your location, and your friends. That is, FOAF is syndicating yourself, just like RSS syndication of your blog or website.
You might find these links useful.