But locals are lashing out at the wrong targets. The most striking example was the crushing rejection last month, in a public vote, of a waterfront condominium development called 8 Washington. The citywide vote turned into a referendum on gentrification; city politicians' positions on 8 Washington became a proxy for their vision of what San Francisco should be. The city's tenant-rights groups, of which there is no shortage, are surprisingly sceptical of plans to add to the city's housing supply. Some contend that so long as there is "infinite" demand for housing in San Francisco, constructing apartments will somehow raise prices for everyone else. Others hate the sight of luxury flats going up when low-income folks are being priced out of the city. But those apartments can be flogged to newcomers who might otherwise be attracted to townhouses in the Mission.

Some of the other spasms of rage are even sillier. I tried the $4 toast when I was in town last month. It was generously sliced, came with a fancy sea-salt and peanut-butter spread, filled me up for several hours, and actually cost $3.75. This was not a price that filled this native Londoner (or, one hopes, The Economist's accountants) with outrage.

Anger at the Google bus is slightly more understandable. Perhaps 14,000 workers travel to work in Silicon Valley each day on private buses provided by their employers. San Francisco's public-transport system is creaky, and "Google buses" (many of which are actually organised by Facebook, Yahoo, etc) often pick up their charges at public bus stops. That is not technically legal (although the city is working on it), and it's got to be annoying. But the slogans displayed at yesterday's protest—"stop evictions now!"; "San Francisco, not for sale!"—suggest that other animating forces were at work. The Google buses are one of the most visible signs of the changes San Francisco is going through, and many locals are unhappy about those changes. But would they prefer those 14,000 techies take to private cars, further clogging up the already-congested 101 freeway?

Finally we have today's delightfully insensitive remarks from one Greg Gopman, CEO of something called AngelHack (Twitter bio: "Believer of dreams"), whose crude comments on vagrancy and poverty in San Francisco seem so perfectly calibrated to tweak the buttons of the city's growing anti-techie brigade that one is tempted to believe he was actually dreamed up by Art Agnos. Anyone whose conscience permits them to write sentences like these...

You can preach compassion, equality, and be the biggest lover in the world, but there is an area of town for degenerates and an area of town for the working class... It's a burden and a liability having them so close to us. Believe me, if they added the smallest iota of value I'd consider thinking different, but the crazy toothless lady who kicks everyone that gets too close to her cardboard box hasn't made anyone's life better in a while.

...deserves to have steaming piles of cyber-scorn heaped upon them (Mr Gopman apologised after his Facebook post, now deleted, went viral, as of course it would in San Francisco).

But it is hard to visit San Francisco, particularly after having heard so much about its booming economy, and not be surprised by the seediness of parts of the heart of the city. Twitter and chums may have spruced up the mid-Market area but you wouldn't want to find yourself walking around late at night. The proliferating coffee shops and start-ups of nearby SoMa share the streets with a large homeless population. And the Tenderloin is a bizarre "island of poverty and squalor", as this excellent article puts it, of a kind rarely seen in developed-world cities. The point is not that Mr Gopman's remarks are in any way defensible. It is that the problems he describes are not phantoms, and that San Franciscans might more usefully spend their time thinking about them than gleefully sharing the latest idiocies to pop up on their Twitter feed.

(Photo source: Wikimedia commons)