Anonymous on Facebook
It's interesting how people think that Facebook does not know who you are just because you don't give them your real name. Between your activity, the activity of your friends, the info you friends have on you (email and phone) Facebook is able to build out a pretty solid profile on you. Facebook knows who you are. They know who you are even if you don't use Facebook so not hard to connect you to an account, even if not under your own name.