Facebook goes behind your back to present your profile to people you’ve chosen not to friend
While Facebook makes it clear that they will not store the password for your email account, what they don’t make so clear is that they will store the addresses of everyone it found in your email account and keep them associated with you, even the ones that you chose to skip. So how does Facebook use this information? They present you as a possible contact to the people that you skipped – even if that person has never shown Facebook a connection of any kind to you. Nice, eh? Effectively, Facebook is ignoring your preference to not contact these people by going behind your back to ask them if they want to friend you.