So when I see stories with very poor grammar and punctuation, bordering on chatspeak or textspeak or whatever these crazy kids call it these days... I question whether the author is telling the truth about being over the age of 18.
Seriously. Think about it a moment. Most of us have figured out by age 18 how to write, if not 100% correct, at least close enough to get by pretty well. The few exceptions I've found have been the kind of people that don't enjoy writing and wouldn't do it in their free time, or didn't have English as their first language. I don't think grammar is a lost art though, in fact, I think we're seeing a renewed interest in it by the number of grammar snobs that are cropping up. It's like the technologically literate are starting to push back against the illiterate that are infiltrating their domain. We went from using 1337 to set ourselves apart to using perfect grammar while online to set ourselves apart from the people that don't type as well as we do...
On websites other than this one, I just assume simple ignorance or not enough experience with typing, thereby making the person more likely to take shortcuts.