https://www.cnbc.com/2019/01/30/facebooks-sheryl-sandberg-defends-research-app-says-users-opted-in.html > Facebook users went through a "rigorous consent flow" before participating in its market research program, Chief Operating Officer Sheryl Sandberg told CNBC's Julia Boorstin on Wednesday. > Earlier Wednesday, Apple revoked some developer privileges after TechCrunch reported that Facebook paid some users to download an app that enabled the company to track user behavior on their mobile devices, including private messages.