Yeah, that's the problem. Unless I personally build a trust score for every member in the web, all I can do is rely on a score based on friend-of-friend rankings. Eventually a friend and I will disagree on a friend-of-friend ranking. Do I lower the trust of the friend, or the friend-of-friend? Is that even possible? And if it is, how much time do I really want to spend pruning the web?

Good example: I want to see everything my Aunt Susan is doing in her personal life on Facebook. I do not want to see anything ever for any reason that has to do with her Zynga games.

A single trust score doesn't really encapsulate that relationship and it's very possible she would effectively breach the WoT by allowing Zynga to send me messages, notices or e-mail in exchange for her to get a shiny new Farmville tractor or something.

I stopped using Facebook because of this kind of crap. I don't have the time, energy or interest to deal with people I do know sending me crap I don't want, and more importantly Facebook's flexible definition of privacy and customer service. I had Facebook change my settings away from their desired state more than once as part of an "policy" or "feature" update.

So I guess the meta discussion is about whether you trust the holder of the trust. LOL.