Build a game, and they will play--and pay. Of the 62 million Americans who will log game time on a social network this year, some 10% will open their real-world wallets to buy virtual goods. That small percentage is nothing to scoff at, says Paul Verna, analyst at eMarketer. "It's like gambling," he says, encouraging companies to pursue repeat purchasers, a lesson of this London conference. "It's little bits at a time, but it becomes substantial." He's not kidding. The small population of purchase-happy gamers in the U.S. will spend an estimated $653 million on virtual goods this year. Game on.
A version of this article appears in the November 2011 issue of Fast Company.