I agree w/ Dogdinger to a point. Perhaps not so finite. I think that society in general has slipped on the importance of proper grammar and spelling. It is more difficult to take one seriously when they can not come close to proper spelling and sentence structure.
It's kind of like "Ebonics", I'm fairly sure that we do not want our children taught in this, because we know that it is not a recipe for success.
I think that part of it is the age of computers. I notice that my kids going through school don't seem to have near the importance placed on legible hand writing and spelling that I did when I was a kid. They are taught that participation is good enough. They should be taught to participate accurately.
PS. I can not spell well at all, I use the spell check that is at the top of the page in my tool bar.