Right now the most innovations in language use come from internet language. This is a totally different kind of beast out there, but in general it leans toward the informal side.
Our intuition (plus corpus data) towards the grammaticality of language relies heavily on written language. We really cannot picture what kind of Chinese youngsters are speaking among their peers, in the Internet cafe or in their dorms.
Should there be a standard language called standard Chinese? That is a question.