*applause* I agree on all of those points, even if I'm guilty of some of the bad ones and probably don't do the good ones often enough. An addendum:

If English is your native language and yet you can't spell and refuse to use spellcheck because it limits your style or it's too much trouble or "everyone can understand me anyway", I probably don't like you.

People like that are bad. People who use slang, AOLspeak (u, ic, 4, neways, etc.) and l33tspeak on purpose; or misspell things on purpose (like this one person on a forum I visit who initially insisted on using "E" instead of "I", "butter" instead of "but", and a few other variations I can't remember right now), because it "sets them apart from the crowd"; well, people who insist on doing that, even if it makes what they write largely unreadable, make me want to kill them. Especially if they do that in fanfiction.