I did an experiment a few years ago where I set up a profile for someone who supposedly went to my university. His pictures were pulled from the profile of a male model, the rest was all made up. I went through every profile I could get and sent friend requests. I actually hit the 5000 friends limit. Usually I would send a message saying "hey we met at X party last night!" if I could find that information on their public profile. Many of the people "remembered" that. The account still gets people wishing him happy birthday.