We want this time to be different so badly, we can almost taste it.

If you visit San Francisco, you will find it difficult to walk more than a few blocks in central S.F. without encountering a major construction project. It seems that every decrepit low-rise building in the city has been razed and is being replaced with a gleaming new residential tower.

Parking lots have been ripped up and are now sprouting condos and luxury rental flats.

This boom is not overly surprising, given the centrality of San Francisco and the S.F. Bay Area in the Hipster-Techie Mental Map which I have sketched here for those who may still suffer from delusions that Washington D.C. and New York matter--(hint: they don't.)

The influx of mobile/software tech into the S.F. Bay Area has triggered not just a boom in tech but in all the service sectors that cater to well-paid techies. This mass of new people has created traffic jams that last virtually all day and evening, and overloaded the area's BART transit rail system such that trains at 11 pm are as jammed as any during rush hour.

This phenomenal building boom is truly something to behold, as it has spread from S.F. to the East Bay as workers priced out of S.F. move east across the Bay, driving up rents to near-S.F. levels.

Yes, rents and home prices are starting to soften, but this hasn't changed the general view that this is only a moderation of a long-term uptrend with no end in sight.

This is of course a modern analog of the Gold Rush in the 1850s, and the previous tech/building boom in the late 1990s: an enormous influx of income drives a building boom and a mass influx of treasure-seekers, entrepreneurs, dreamers and those hoping to land a good-paying job in Boomland.