How Facebook figures out everyone you’ve ever met
▻https://gizmodo.com/how-facebook-figures-out-everyone-youve-ever-met-1819822691
Having issued this warning, and having acknowledged that people in your address book may not necessarily want to be connected to you, Facebook will then do exactly what it warned you not to do. If you agree to share your contacts, every piece of contact data you possess will go to Facebook, and the network will then use it to try to search for connections(...)