BVB said:Hit a nerve, eh?
Only in the sense that I find grammar-nazis to be more of a hindrance than a help when trying to communicate with people.
Is the suit in your allusion a tuxedo or just a matching sweatshirt and pants? Is the party BYOB-And-Get-Wasted affair or an annual company formal affair?
And anyone who pretends that I might mean "formal affair" when I say "causal" is doing both of us a disservice.

These message boards are clearly not a corporate formal dinner party. Just as clearly, neither are they Friday night fraternity drunken debauchery.
Because, yeah, appearances DO matter. You never get a second chance to make a first impression, and on the Internet, every message is someone's first impression of who you are.
Yes. That includes the impression of being a stuffed shirt with no sense of humor or flexibility for people's foibles. These boards are centered on discussion of a hobby, something one does for fun in one's spare time. While clarity is nice, requiring formalism detracts from the fun. As Wulf Rathbane mentioned, the style should be chosen to fit the audience. Does this look like a formal audience to you?