it's not necessarily the facebook app (if you have it disabled), but most free and even paid apps are 'phoning' facebook and sending up data when you open the a

it's not necessarily the facebook app (if you have it disabled), but most free and even paid apps are 'phoning' facebook and sending up data when you open the app (as part of the FB SDK). This is what became big news recently. I've noticed it for years and thought it was widely known. There are apps that will try to hit graph.facebook.com before they even connect to their own services. You can install a VPN based firewall to block this behavior.