It's like playing "Degrees of seperation." I am and have been in the past friends with a TON of people, none of whom know each other. So, basically I cast a line in the water - if nobody knows who someone is, where someone is now and how to contact them, I have to just take a stab at guessing who their other friends may have been and pulling them out of the school phone directories I have lying around from years past, which never seen to include anyone that I'm looking for. After explaining to them why in the hell I'm bothering them, they either tell me someone else who they think might know, or tell me that they have no idea. And so it continues.
Sometimes I wonder if I might get better results just posting an ad on Craigslist.
Sometimes I wonder if I might get better results just posting an ad on Craigslist.