I couldn't quite put my finger on my misgivings about FOAF, but then I read some of the LinkedIn coverage (among the in-crowd, natch). My issue is this: FOAF seems way too explicit.

Is there a non-identifying FOAF vocabulary? For example, I'd love to build something which identified people only by hash-of-identifier. (Happens I have a really great dataset for that, running in Groove all day). A visual interactive network map would be really valuable, but just cannot identify by name any people you don't actually know, or shared spaces you don't belong to. Whereas, a hash-of-ID FOAF might allow mapping without identification.

This would leave it to each person in the network to resolve their known values, so naming the people they actually know. Like LinkedIn, Friendster etc, you'd gain the nice socialness of having to politely request introductions via mutual acquaintances.