Great story, and a great insight to why social networking sites are in existance today. I think you hit the nail on the head when you said the reasoning behind these sites isn't to reconnect with old friends and find new ones; it is to group people into certain segments to market products to them. Why else would every major company now end their marketing campaigns with "Friend us on Facebook or follow us on Twitter". They see that traditional advertising (television, radio, newspapers) is failing to bring in the revenue that it used to, so they are looking for alternate means to get consumers to buy their product. And that in itself is not necessarily a bad thing, but luring people into a social network site, gathering their private information, and lending that to the highest bidder without expressly telling the users that this is one of the functions of the site is just wrong.
And again, if I wanted to reconnect with people I went to high school with, I would, oh, I don't know...
F*CKING CALL THEM!!! The notion that I want to be in contact with everyone I went to high school with is ridiculous, as many of the weren't my friends, and some of them were downright assholes to me. In fact, my wife had a run in on Facebook with a former boyfriend whom she "friended" on the site. He decided as a malicious prank to post some unflattering pictures of some of the things she did in her college years. Nothing pornographic or debaucherous (is that a word?), but as she had professional contacts as Facebook friends as well as personal friends, these pictures were a bit of an embarassment. No real problems came from it, but it just showed that people online can be dicks. So keeping your identity secret online is something that I would put some creedence in.
Joe -- On that subject, did anyone else have to provide a social security number to become a forum member???

-- Anthrax