^^^ It's the internet, right? If you know how to write, you can hide intonation and speech patterns, and therefore, sound however you please, whenever you please. It's similar to kickin it w/ your friends and writing for your english teacher. You can talk however you feel to your friends, but if you turn in a slanguage-laced, ebonics-infested paper, you're not going to pass.
My point is: if you know how to speak/write properly, you can present yourself in any way you please. You can call it "fake," but language or verbal representation of yourself does not necessarily represent who you are or your background, especially if you've had the right to an education.