How involved is/was Matt Groening

[Mr. Manager]

While watching episodes of The Simpsons or Futurama, I rarely see the words " written by Matt Groening" or "directed by Matt Groening". How involved is he?
Does he really do much for The Simpsons? How involved was he in Futurama? Did he just work on the series bibles and then write nothing else or am I just naive? Is he too busy with his comic strip?

Edit:Oops! I forgot the question mark in the title!

[J. B. Warner]

Well, given that he created the show, he keeps a fairly watchful eye on what the writers and executive producers are up to. He did this less frequently from 1998 to 2002, however, as he was more heavily focused on "Futurama" at the time. But he's still conscious of what goes on in the makings of the show.

He also wrote the Season 3 episode "Colonel Homer".