Its a legitimate theory. IF the media is liberal, then they are alienating a
portion of the potential audience. That might explain why ratings for the big
3 network news shows are dropping and Fox is rising. But it also begs the
question whether the networks aren't rational capitalist organizations - viz,
why allow this situation to continue. Here is the Stanford/UCLA study (Doug,
potshots away):

http://mason.gmu.edu/~atabarro/MediaBias.doc