Broadcast Television: it goes through the ground and its free to viewers. It has mass media moments like the Super Bowl and provides shows like American Idol so you can call in and vote on the singer who has the most talent (or lack there of, but is hot).
But the facts are that the top 35 advertising supported cable networks has had a 7% increase in total viewers this season while the broadcast networks are down 5%. Cable networks are still able to create revenue through their ad sales, and broadcast TV can't say the same. It's been mentioned in various articles that there is a growing consensus among viewers that there is no real differentiation between broadcast TV and the top cable networks. Why have a split in TV stations if no one actually cares about the differentiation. If cable or network TV was allowed to air racy shows with no commercials like Cinemax, HBO or Showtime, then those subscription based stations would be gone as well. Network TV needs to offer audiences (and advertisers) something more than the Super Bowl to survive.
It's funny to think that perhaps in the next few years when this course is taught that Broadcast Network TV may not even be a sector anymore.