and now for a few pessimistic perspectives on explicit approaches to defining social relationships. i was going to write a much longer post, but i don't have time, so if you're looking for something coherent you might want to look elsewhere:

david weinberger on "social bullshit" :

"Third, real social networks are always implicit. The ones constructed explicitly are always -- yes, always -- infected with a heavy dose of social bullshit. It's like thinking that the invitiation list for your wedding actually reflects your circle of friends and relatives."

Dr Ont's Semantic Spout" :

"TypePad produces the worst FOAF in the world. Take this typical example. Apparently this geezer 'knows' BBC News! I know that this particular foaf:Person is a British Member of Parliament but surely not even these super-humans can know 'things'. And Ross himself seems to know a lot of inanimate objects."

ross mayfield understates the obvious :

"Expect fast growth of this service within the explicit crowd, but not everyone wants to be so explicit, the absence of constraints and bad data will hamper its utility."

and quite related to all this, i'm going to have to agree with the assessment at startupskills :

"My point is that outside of perhaps a novel niche application here or there, the idea itself will never get beyond the early-adopters because (to my knowledge) no one has demonstrated a credible model in which an average person would willingly adopt it."

i don't think i'm mistaking intentions for actions either . rather, given the obvious facts that most people won't see the value of joining the network [ unlike music sharing ] and those that do see the value will be stymied by a signal-to-noise problem which will become more of a problem as the network grows, i see big problems for the adoption of decentralized "social software" as it's currently envisioned.

i'm guessing that it will be 3-5 years before any of this shakes out into anything that can be adopted by mainstream ISVs looking for new business opportunities - just look at how long the rss fiasco has be going on and rss is easy.