In the early 1960s, computers haunted the American popular imagination. Bleak tools of the cold war, they embodied the rigid organization and mechanical conformity that made the military-industrial complex possible. But by the 1990s-and the dawn of the Internet-computers started to represent a very different kind of world: a collaborative and digital utopia modeled on the communal ideals of the hippies who so vehemently rebelled against the cold...