Question of the Day: How much should parents in general know about their teenagers’ life online? Why?

I don't believe that its mandatory for a parent to know about a teenagers life online. If a parent wants to know certain things, i feel that its okay for them to know bu i don't think it should be a "supposed to" type of thing. I believe that teens are old enough to know right from wrong when it comes to being on the web therefore they dont need a supervisor down their back whenever their on the computer. If a teen is willing to add their parent to that part of their life its okay.