I equate them to politicians who instead of debating the issues choose to argue about something completely unrelated, for example swift boating.
I think it depends on the situation. Sometimes, grammar really can make a difference in the meaning of a sentence. For the most part, though, grammar policemen are just being pricks.
I think its wierd when people always freak out alot about grammer: especially on a message bored on the internet.
I'm ok with grammar police in general.... it's just that some of them are kind of weak. Might not have a life.
I know my grammar isn't perfect, but some posters totally leave out punctuation and their posts make no sense. The posts that really get to me are the ones you usually read on commenting sections, such as ESPN or YouTube, and Twitter ( I understand Twitter only allows a certain amount of characters so it is hard to type correctly).
I enjoy both learning and teaching about the English language. I don't correct people on message boards though, since, well, it's a message board.
Depends on the extent of the foul. Punctuation, no. Spelling, not most of the time. Those kinds of things are idiotic to point out. Especially with people posting from mobile devices these days. But I cannot stand people that purposefully type with stupid abbreviations and stream-of-thought type sentences.(I'm sure I'm guilty of this to some extent, though) And yes, I give your post less merit if you type like this. (Cue response in said form)
A lack of proper punctuation, misspelled words and the like are to me signs of someone who either is uneducated (not necessarily stupid) or just plain lazy. I don't do much correcting of them but I have to admit it drives me crazy to read these types of posts. In my opinion, if you are ambitious enough to post, at least be ambitious enough to do it correctly.