You learn this stuff in elementary school. If someone doesn't know the difference, I automatically disrespect him. And english isn't even my mother tongue.
I agree. English is my second language and I frown upon Americans who do not know the difference. I would not disrespect them nor would I be judgmental because people can make mistakes.
Native English speaker here from America. Same here, if they're young I guess I can ignore it, but there should be no reason to get grammar so botched with instant info so close at hand.
I've known the difference since I was like 8 and I always use the correct forms of you're, your, too, and to. it really frustrates me when people don't use them correctly, even when texting or instant messaging.