Rake-thin and bearded, Dorsey radiates a sense of composed quietude. Walking and talking around Twitter’s offices, he has the air of a docent showing off a collection of Donald Judd sculptures. He wears a white T-shirt, black jeans, and laceless, orange high-tops that look like they’ve been painted from a bucket of melted creamsicles. “What’s interesting about Twitter is that the value is not the social network you bring to it,” Dorsey says. “It’s actually the people you meet around interests that you discover.” —Bloomberg