Lee has been credited with catalyzing San Francisco’s tech boom early in his term by passing a business-friendly tax-exemption that he (correctly) predicted would help lure economic development into a distressed part of town. Called the Central Market-Tenderloin Area Payroll Expense Tax Exclusion, it waived payroll taxes for companies whose payroll exceeded $1 million in exchange for a community benefits agreement, and a commitment to build in the Tenderloin area. After Lee used the exemption to harpoon Twitter in 2012, it became sourly known as the “Twitter Tax Break.” Other tech companies like Uber, Airbnb, Pinterest, and Dropbox followed Twitter into the city, bringing with them municipal grants, large philanthropic donations to non-profits, and increased local purchasing—in exchange for whopping tax breaks diverted from the city budget.

https://www.bloomberg.com/news/articles/2017-12-12/what-ed-l...

Without Ed Lee's tech friendly policies, San Francisco's tech industry might have never boomed the way it did.

As a resident of San Francisco from before the tech era, during, and after, I can recall just how awesome and transformative the first wave of tech companies were to the city. Those companies were Twitter, Uber, Airbnb. Maybe a few more that I forgot. They kick started the tech wave. Many tech companies spawned from larger ones.