On October 27, 2012, Facebook CEO Mark Zuckerberg wrote an email to his then-director of product development. For years, Facebook had allowed third-party apps to access data on their users’ unwitting friends, and Zuckerberg was considering whether giving away all that information was risky. In his email, he suggested it was not: “I’m generally skeptical that there is as much data leak strategic risk as you think,” he wrote at the time.