Why Twitter's headquarters is in one of San Francisco's worst neighborhoods

In a post on Quora, Twitter co-founder Ev Williams explained why the social network moved its headquarters to the Tenderloin, one of San Francisco's worst neighborhoods.

(Depending on how much of a San Francisco stickler you want to be, Twitter's headquarters is technically in Civic Center/Mid-Market, but the neighborhoods have a lot in common.)

The obvious answer is that it was for the tax breaks: As part of an urban renewal initiative, San Francisco offers a temporary exemption to its 1.5% payroll tax to any company who sets up shop in the neighborhood - tax breaks that cost the city $4.2 million across the 15 companies that took advantage, according to a 2014 report.

But Williams writes that while "many factors were considered," the tax breaks weren't one of them.

"I can tell you with certainty, though, that at our initial point of interest in the building, we knew NOTHING of the tax breaks (and that, without them, there is a good chance we would have moved out of the city)," Williams writes.

At the time, rumors were swirling that Twitter was considering a move outside of San Francisco proper, to the surrounding cities of South San Francisco or Brisbane.

Instead, it goes back to 2010, Williams recalls, when he was walking down Market Street, and told his wife Sara "how it's a damn shame that the middle of San Francisco was so run down and empty."

The Tenderloin, which sits right in the heart of San Francisco, is in the shadow of City Hall and wedged right up against the more photogenic downtown neighborhoods like Union Square and Hayes Valley.

A common urban legend around these parts is that the Tenderloin gets its name because the neighborhood was so bad that San Francisco city cops, during the turn of the 20th century, had to be bribed with high-quality meat to be willing to police the area.

And so, Williams wrote, he thought that Twitter could do some good for the neighborhood, bringing in thousands of employees every day as a "revitalizing force." Plus, the building that Twitter chose for the headquarters - a fortress-like structure formerly known as the Furniture Mart building - had "the largest floorplate (by far) of any available building in the city."

"[At] least I saw the location as a pro rather than a con," Williams writes.

Twitter's real estate brokers were apparently not including the location on their "short list" due to its location.

But with Williams excited by the opportunity, Twitter asked its real estate broker to move that building to the top of the candidate pile. Williams and company then toured the building, undeterred by what some might have considered a bad omen:

"We went and toured it, and there was a guy taking a dump on the sidewalk outside," Williams writes.

Here's what Twitter's neighborhood looked like in 2011, shortly after it announced plans to set up its headquarters in the Furniture Mart building.