What is a "real name" anyway in this context? Certainly Facebook does not require a "legal" name to sign up, and any remotely plausible name seems to work.

Several of my friends and I use full or partial pseudonyms on Facebook; (In fact, I've changed mine multiple times.) As an alternative to that, my girlfriend keeps different Facebook accounts logged into different browsers to keep her personal and professional identities separate.

Identity is fluid, seems so should the names we employ in this even more volatile medium of the web.