https://phys.org/news/2019-01-facebook-paid-users-track-smartphone.html > The news could be a further embarrassment for Facebook, which has been under heightened scrutiny over failing to crack down on manipulation of its platform and for sharing private data with its business partners. > Facebook said it shut down the application on Apple's iOS on Wednesday after the TechCrunch article was published. It remained unclear if it remained active for Android users.