You all miss the point. mkay, as in the South Park satire, was used by a smug, patronising teacher who says it after a lesson in a tone of fake understanding and empathy with his listeners. Nobody would use it as a substitute for 'okay' except tongue-in-cheek, mkay?
Mkay is slang that is used by most anyone, it is indeed a replacement of "okay" but IS NOT a grammatically correct word. The word was also made very popular by a character in CMT'S animated show, South Park.
made famous by mr. garrison in the south park movie mkay was to take over from saying the word fuck. though it is more commonly used today as a general cooler way of saying ok. it is also used commonly in chat rooms.
