Why do I need to confirm my mobile phone number to get back into my account?
We care about the security of your account, and want to make sure that the only person with access to your Facebook account is you. One of the ways we do this is to ask that you provide your mobile phone number.
To confirm your account, you'll need to log into Facebook and follow the on-screen instructions to add your mobile number. Your mobile phone number will be added to your profile, but you can choose who can see it using your privacy settings.
Why do I see an ad in my homepage about increasing my account protection? Is this really from Facebook?