Stereotypes in Animated Sitcoms: Helpful or Harmful?

Within the last ten to fifteen years, shows like South Park, Family Guy, Futurama, and American Dad have been popping up, creating huge hordes of followers and dominating the airwaves. These shows are unique in that they are animated, which allows for extremely off-color, inappropriate, or even offensive stereotypes. The question is: Are these stereotypes positive or harmful?