Silicon Valley, and San Francisco, have long been been the capital of America's tech economy thanks to a variety of important factors. and , who have all recently left the Bay Area, per a report from The Information. Silicon Valley has been a fertile breeding ground for launching and growing tech companies in a self-perpetuating ecosystem that's survived cycles. Other cities have tried to woo tech dollars and founders, from Salt Lake City's "Silicon Slopes" to New York's "Silicon Alley." Twitter headquarters on April 26, 2017 in San Francisco, California.