It looks like FOAF (Friend of a Friend) is going nowhere. FOAF is one of the better RDF vocabularies out there. And the adoption rate is tiny. The idea is great: formalize social networks so that software can support it. We have tools to create FOAF files automatically, wordpress does it well, so we cannot blame the failure on the lack of tools to generate the necessary RDF. I think FOAF is the right approach to social networking: distributed and sufficiently simple.
What we seem to be missing, are tools to use the RDF. It is easier to formalize something than to provide a useful enough function for the formal description. Yes, all formal descriptions might be useful, but it needs to be very useful so that people will be motivated to use it. This is why unstructured data dominates the world. This is why the semantic web is not picking up steam.
Shameless plug: I have written up an introduction to RDF in French as part of my online XML course.