Facebook has been paying volunteers money each month to install an app on their phone called ‘Facebook Research’ according to a report from TechCrunch. This application watches and records activity and actions on a phone and sends that information back to Facebook.
The app offers people between the ages of 13 to 25 up to $20 per month for almost complete access to their phone's data. Specifically, the app installs a custom root certificate which granted Facebook the direct ability to see users’ private messages, emails, web searches, and browsing activity – while also requesting users to take screenshots of their Amazon order history and send it back to Facebook for review.
Facebook was originally collecting an amount of this data through Onavo Protect, a VPN service that it acquired back in 2013. It is suggested that the data Facebook has collected through these methods has helped it to spot current or future competitors, which then allows them to acquire or clone them.
The Facebook Research app was removed from the App Store about 6 months ago after Apple complained about it violating its guidelines on data collection.