Facebook paid users to collect data from their phones
https://finance.yahoo.com/news/facebook-pays-users-to-collect-data-from-their-phones-160557945.html
The app was called “Facebook Research” and through the VPN, the company was able to collect all of the data it needed. Facebook used beta-testing services Applause, BetaBound, and uTest and operated under the name “Project Atlas” to mask the company’s direct involvement, according to TechCrunch.
Initially Facebook vigorously defended the entire operation, but shortly after announced that it would be ripping the app from iOS devices.