https://www.mercurynews.com/2019/01/30/facebook-pulls-app-that-was-paying-teens-for-access-to-their-phones/

Facebook has been paying users as young as 13 up to $20 a month in gift cards for almost total access to their phones, a practice it now says it will stop among iPhone users because it’s a violation of Apple’s policies.

The company asked users to install “Facebook Research,” a virtual private network (VPN), on their mobile phones so that it could see almost all activity on those phones, TechCrunch reported Tuesday. Facebook admitted it was gathering usage data through the app, and said it would stop doing so among iOS users.