Being at the opening of the world’s first Bitcoin conference was like showing up for the first day of camp—a boys’ camp—and finding that everyone already knew one another in an alternate universe. For a couple of days in August, the Roosevelt Hotel in New York City served as a real-world meeting place for about 50 people who had spent months riffing with one another on the phone, in chat rooms, and over Skype. They came to talk about how Bitcoin could change the world—and how it could make them rich.