Lowell Winer was at his office in Irvine, California, when he got a phone call: Sam Altman wanted a meeting. It was 2005, and Winer had no idea who Altman was. Altman told Winer, who was head of business development for Boost Mobile, that he’d been referred by a representative of the wireless brand’s parent company, Sprint.Altman was the chief executive officer of a tiny, struggling startup called Loopt, which he founded earlier that year at the age of 19. The idea was to use a cellphone’s GPS c...