New Delhi, Oct. 15 -- It was a warm, cloudless afternoon, the kind San Francisco saves for early autumn. The Ferry Building tower clock, which has kept time over the waterfront since 1898, chimed as I walked north along the Embarcadero, the road that runs beside the bay.

"San Francisco. The City of Firsts," proclaimed posters wrapped around light poles. Most advertisements I passed featured artificial intelligence, or AI -- the computer programs that can now write, talk, recognize pictures, and make decisions -- visible on buses, shop windows, walls, and billboards, even banners trailing from two small planes that circled the Bay.

I was in town for SF Tech Week, 5-11 October, a citywide series of talks and gatherings, organized by a16z ...