IF the renter is putting in a request and has not booked with you yet, it's because AirBnB is trying to deter from the potential of you and that potential renter booking off the site and therefore AirBnB does not make money off the booking. Once they have booked with you, you're given the person's contact phone number and their last name. If one of their verifications is Facebook, then you'd be able to look them up using their full name. Same with trying to give each other your phone numbers during the inquiry phase. It will block the phone number as "sensative material hidden." You can't even type Facebook or even FB in a message to someone that has not booked with you yet without it getting blocked.