I can't help the fact that I'm a really good speller or that I know the intricacies of English grammar. I just kind of picked it up during my many years of intensively studying linguistics. I can't stand to not capitalize things that should be capitalized, or to misspell words. If I know perfectly well how it should be properly written, and I know how to use the backspace key, I can't rationalize to myself sending out a message that contains errors like that.

But I'm not going to heckle everybody who doesn't like to use proper grammar and spelling on the Internet. It's about as futile as trying to build a robot out of toothpicks. As long as you write intelligibly, I don't have a problem.