Remember when Facebook kept asking to use our phone number to secure our accounts with two-factor authentication?
People can now use that same phone number to look you up on Facebook. Facebook at this time is not giving you an option to opt-out. Default settings right now allow anyone and everyone, with or without an account, to look up a user profile based on that phone number they hounded us for.TechCrunch
TIP: Go into the Settings of your Facebook account, click Privacy, then click “How People Find and Contact You.” Then click “Who can look you up using the phone number you provided?” and change the dropdown box from “Everyone” to “Friends.”