Digital Economy guru Andrew McAfee says there's a new reason for optimism: we're past the point of 'peak stuff' - from here on out, it'll take fewer resources to make things, and cost less to lead a comfortable life. This turn of events invalidates the predictions of overpopulation alarmists and those who argue over how much is enough. What has made this turnabout possible? How we finally stopped using up the world - and what happens next.