Back in YU

Im not sure if you guys know how facebook works, ut your supposed to "friend" anyone that you have ever said hi to. Now that Im back in YU i see all these "friends" and im not sure what im supposed to do. Do I go over and say hi? Should I ask them how there summer was? Or ask why he was hanging out with girls dressed inappropriately and then putting the pictures on line for random people you just see once in your life, like me, to look at.

oh how excited I am to be back in YU