It's called Four Traits Writing. Basically, it addresses one of the really outdated parts of Six Traits which is a real weakness. Six traits doesn't have a framework to address the type of writing. All writing is considered the same and measured against the same rubriques. But this makes no sense to the students.
The problem is that students today are writing far more than most previous generations. But they are doing it as chats and texts, not as formal long form essays. Four traits writing addresses this and provides a framework so that the audience and media are considered. Really, this comes to purpose of writing. Below is the original mateirals from 4 traits writing which could definitely and should be updated. In terms of usage, I imagine this could be integrated in writing in either:
The Types of Writing
Blending Writers Workshop
Student Writing Practice