Grammar, Punctuation, Spelling, etc.

[Treebeard's apprentice]

This has been mentioned in the "your very own avatar" thread, but I would like a new thread devoted specifically to this subject.
I've noticed, especially on the internet, that the rules of spelling, punctuation and the like are broken and in some cases completely disregarded. Many of these instances might be accidental or developed into habit by everyday speech, but sometimes it's ridiculous. Aren't these things supposed to be taught in school?
It may not seem like a big deal, but it just drives me nuts! How are we supposed to understand you if you don't attempt to make yourself legible? I'm sorry, but I thought the members of a site devoted to a great philologist would be especially wary of their writing.

Any other people who need to vent their grammar-rage? What in particular bothers you? Or are you guilty of these atrocities against the English language? Please share.