A Stigler Center panel explores the implications of big data for competition policy and for consumer welfare.     The business model at the heart of the digital economy is a simple one: Internet giants such as Google and Facebook provide consumers with “free” services—free email, free GPS, free instant messaging, free search—and in return consumers consent to hand over vast amounts of their own data, which the companies then use to target advertisers.   This exchange helped make data the “new” oil, creating “new infrastructure, new businesses, new monopolies, new politics and—crucially—new economics,” according to The Economist. To a large degree, …