I'm deeply saddened by the intellectual deterioration occurring in modern society, and bad spelling & grammar are an indicator of it. How depressing is it that it's currently fashionable to be stupid? That being said, while I do notice bad spelling and grammar, I don't point them out to people or anything, and I have friends who can't spell well and often use improper grammar. The only thing I do bother flaming is AOLspeak - people who say something like "y 2 plz b ur" aren't making legitimate errors, nor are they being lazy & saving time - simply put, they are trying to fit in with people I loathe - stupid children.
PS - In our global society it's essential to realize that not everyone speaks English natively. While I'd love to believe this accounts for all of the bad spelling and grammar I see, sadly most non-native speakers write English better than most native speakers. This is because, unlike native speakers, those learning the language actually bother reading it once in a while.