game has 20,000 viewers. cnn s biggest audience in history. the previous record was set back in 1993. that s when al gore and ross perot debated nafta with 16.8 million viewers. now this debate even bigger. why do the ratings matter? all those candidates on stage had a huge opportunity to swag te sway tens of millions of voters. 23 million viewers is the average of the viewer ship for those 180 minutes. it turns out the prime time debate reached 37.9 million people. those are amazing numbers in television. fox s debate averaged 24 million. this is the biggest show of the fall. what is causing all this?