This is a fairly old blog entry (4 months) but I hadn't seen it before, it discusses another social software format, XFN.
Social software snippets "So Jonas poses a good question, why was FOAF invented? Perhaps an attempt to justify RDF? Is this an example of a solution looking for a problem? A clever acronym looking for a reason to exist?
Speaking of which, the biggest irony I see about FOAF is its name, which stands for "Friend of a Friend", and yet the technology has nothing to do with "friends". Like Jonas said, it's simply vCard recast in RDF, except for the "knows" relationship, which itself is quite meaningless (quite ironic for a Semantic Web effort), as it provides no more meaning than a plain hyperlink. Why work so hard for so little?
FOAF could be saved however, simply by adding an XFN module, thus enabling FOAF to finally fulfill its namesake, and represent friendship rather than just claiming to."