So long as someone makes some kind of effort to be coherent, I don't really care. There is no inherent reason why one way of typing is more correct than another. Language is a tool to communicate, and if two people agree upon some form of communication, and it works, then there you go.

There are strange social reasons why people care about such things. People will subconsciously adapt their manner of speech to people they want to befriend, or to a group of people to which they want to belong. It even happens in real life. My own style of speaking has changed a lot since I was a child; people in this area (including my parents) have a strange dialect and I've mostly abandoned it. Some of my cousins who grew up here moved to the south, and they now have a southern accent. I even often find people from America who've moved to Britain end up with British accents.

I also definitely notice that because a lot of people use "proper" grammar around this MB, that many people who come to the MB will eventually adopt the same style of writing after time. It's a way to try to fit in. If you want to fit in, you'll try to behave like everyone else.

Another way to fit in is to draw a line and say "Look at those people. They're not like me. They're also not like you. See? We're part of a group, you and me." A "common enemy" is something that draws people together. Which might be the purpose of this thread, really. I used to do this kind of thing all the time too, but I don't care too much now.