I think you just hit the real problem, right there. These kids get on the internet and every possible rule in the English language that can be broken is utterly demolished. Then they go to school and think that it's all OK to use in formal writing. It's pure laziness, really. My use of the rules of English on AIM is stressed, to be sure, but when I write anything formally, I make sure it's as perfect as it can be. These kids need much more practice.