And now a bit more seriously.
I read a lot. I went to public school in Spain (Madrid). My Masters is in Pure Maths and Software Engineering.
I nearly did a doctorate (here in England) in Psycholinguistics (Acquisition of Languages in Bilingual Families).
And yet all that education hasn't trimmed out all my English little quirks.
You may or may not have noticed before that English is not my first language.
The odd preposition here, the funny word order there. Yep, not English.
When I read a post in a forum, I are more annoyed by lack of meaning than lack of grammar or punctuation.
Yes, my right eye twitches every time I see the word "rouge".
And my left eye twitches when I see "your" instead of "you're".
What with all these twitches, with some posts I have a hard time keeping my eyes open at all.
But imagine these two posts:
"hey im a suttlety lvl 80 rouge and want to no teh best wepomn for me plz thx"
"Dear all. I was wondering whether you'd be so kind as to direct me to the best way of going to Darnassus. Much obliged."
Now the first one has appalling spelling and grammar, but somehow the question is straight-forward and it would be easy to point this person in the right direction.
The second post has perfect spelling and grammar, yet the guy does not seem to appreciate he's not given any information about himself for any of us to be of use to him.
So I guess my point is I care more about clear thought and contents.
How you spell or construct those thoughts is important but secondary.
My two pesetas.