[bherms]

but my experience has been that there is a large group of people from very similar backgrounds (20-something from Stanford/MIT/CMU in the tech industry)

That's why I said "not so much as 10-20 years ago". It seems like our community is actually destroying what made SF so special in years past. That being said, while a majority of people coming in are fairly well-off 20-something tech industry kids, the fact that SF prides itself as being an "anything goes, something for everyone" kind of city helps to bring out the quirkiness and eccentricities of people who otherwise would've never found that side of themselves. In addition, if you look in the right places, you will find a ton of the goofy oddballs that made SF such a special place.