FB and Google have this info but it's figuring out a way to use their API without username, email, etc. to get their data. I don't know if you can do with IP a

FB and Google have this info but it's figuring out a way to use their API without username, email, etc. to get their data. I don't know if you can do with IP address or cookies of some sort since they've already been logged into FB or used Google recently without having them login when they first visit your site. It might not be allowed...