I spent the last couple of days at a conference about climate, cities, and behavior. One topic that kept coming up among the municipal officials there — from places like New York, Denver, Vancouver, Richmond, and San Francisco — was the importance of walkable downtowns to attracting business and investment. Amenities like good transit, bike infrastructure, and dynamic public spaces are increasingly being seen not as frivolities, but as essential tools in building a city’s economy.

In that context, some of us talked about Twitter’s announcement last week that it will be moving to new headquarters in San Francisco’s Central Market neighborhood.

The move was contingent on some controversial tax breaks that the company had negotiated with the city, after threatening to move south to the office parks of San Mateo County.

What makes the Twitter decision particularly noteworthy is the contrast to the move being planned by old-school social media giant Facebook. Its new headquarters will be in  — you guessed it — an office park in San Mateo County. It’s a location that looks positively 20th century.

Facebook, which has 2,000 employees now, will be remodeling the office park to be more like a real city.

Twitter, which could grow from 450 to 2,600 employees in the next six years, will be in an actual city.

The Twitter outcome was made possible because San Francisco officials — hoping to spur the revitalization of a downtrodden neighborhood — were willing to make concessions on the city’s controversial payroll tax. It was a play newsworthy enough to merit the hilarious animated Taiwanese video treatment, see below (thanks to TechCrunch for the link).

Here’s what Twitter’s official blog said about the decision:

We are proud that Twitter will be among the first companies moving into the Central Market area and will be playing a role in its renewal with the city and with other businesses, arts organizations, and the numerous community organizations that have been doing hard work in the neighborhood for many years.

San Francisco’s unique creativity and inventiveness is a part of Twitter’s DNA, and we feel like we are part of San Francisco. Three-quarters of our employees who live in San Francisco are involved in causes and charities in the city. Our employees are excited to be active members of our future neighborhood as volunteers, customers, diners and patrons of the arts.

A San Francisco government official at the conference told me that companies seem to be recognizing the benefits of being in an urban setting — close to companies both similar to and different from themselves. You see it playing out in New York, where more and more tech startups are springing up all around the city, not necessarily in a centralized tech ghetto.

He said it’s about the potential for creative synergy. It’s also about the lifestyle preferences of the young, creative professionals that cities and employers want to attract. Old-fashioned sprawl is just not calling to that crowd.