Yeah they do. I was offered a job after a summer internship but told them I'd only work in California -- after first declining, they offered me a position in SF the next day. When I arrived in SF to start there was ~12% added to my salary for cost of living adjustment over Seattle.
Perhaps they do for SF, given how high cost of living is there. I was told that cost of living increases are not offered, but maybe they were only referring to Seattle?
