I do a lot of my posting late at night, since that is when I do my best writing. At those times, my creativity is at its best, but my math, spelling, and *sometimes* grammar abilities are weak. I marked 'no'.
Let me qualify that. I don't read posts here looking for typos or spelling mistakes, and if there are a few, I don't get bent out of shape over them. I don't feel that the poster personally hates me, or that they are uneducated- believe me, I've met many educated folk with atrocious spelling and grammar. I make plenty of mistakes, especially while trying to post to a topic quickly, or while falling asleep. I read and post to the boards for the industry news, for fun, and for personal edification in an informal environment.
As long as the the basic the criterion of 'getting the point across' is met, I think that quibbling over minutia like a stray comma, an 'i' before 'e' error, or grammar quirk is absurd. Even for many of us who write for publication, a message board is for informal communication.