In my line of work, i am typing for seven and a half hours straight, for government departments and private sector clients also, and i have to be correct, and fast. If not, i get my ass handed to me. So i find that now when typing anything, from forums to instant messages, my grammar, and spelling are almost perfect. Compared to "type it out as fast as i can, who cares if it's right", where i was before i started working here.
But as others have noted above, as long as it is semi-coherent, and not just a mish-mash of letters, it's all good to me