I don't understand why people don't have multiple facebook accounts reflecting different levels of privacy. I facebook-suicided because I didn't want to mix my

I don't understand why people don't have multiple facebook accounts reflecting different levels of privacy. I facebook-suicided because I didn't want to mix my personal and professional lives, and when I contemplate going back to it (mainly for professional reasons) I always have a two-account system in mind. Obviously, I don't use facebook much, so I might be missing something, though.