Why do people on here tend to have bad grammar?

I've seen it a lot, especially in the internet section. People can't even spell the word a and they expect their questions to get answered. What's your opinion on this? One or two typos is ok but constant misspelling just isn't right. Also this Youtube video illustrates what I am saying. a href="http://www.youtube.com/watch?v=Ll-lia-FEIY" rel="nofollow"http://www.youtube.com/watch?v=Ll-lia-FE…/a