The data harvested from our personal devices, along with our trail of electronic transactions and data from other sources, now provides the foundation for some of the world’s largest companies. Personal data also the wellspring for millions of small businesses and countless startups, which turn it into customer insights, market predictions, and personalized digital services. For the past two decades, the commercial use of personal data has grown in wild-west fashion. But now, because of consumer mistrust, government action, and competition for customers, those days are quickly coming to an end.