I doubt any of us use "proper" grammar 100% of the time, if only because there are a lot of grammatical rules that almost everyone ignores.
I take grammatical shortcuts from time to time, but overall try to type as clearly as possible. I'd say 99% of the posts on here are fine. It's only when people go out of their way to essentially talk in caricatures of ebonics or tweet speak that I have an issue. It's like people are actively trying to sound ignorant, which just doesn't seem worth the effort.
Colloquial grammar, perhaps?
Conversational, at least.
It's like the rule that "however" should never start a sentence. One of my professors in a Supreme Court seminar was a stickler for that rule, and would mark us down if we used it. I couldn't help skirting that particular rule by trying to find every quote I could from a Supreme Court Justice starting a sentence that way.
The best one is the "don't put a preposition at the end of a sentence" rule, which allegedly led Winston Churchill to once quip: "This is the sort of English up with which I will not put.”
There's a good joke (well, a joke at least) on this topic.
Person 1: Where's the bathroom at?
Person 2: It's improper to end a sentence with a preposition.
Person 1: My apologies. Where's the bathroom at ________ (insert profane term)?