This indicates an increasing polarization of the news audience: the Right watches Fox, the Left watches MSNBC, and the middle watches CNN. And the middle is fairly small.
I would characterize it as the hard left communists watch MSNBC, run of the mill left wing socialists watch CNN, and the middle watches Fox. Actual right wingers in America who believe in limited government, free markets, individual rights & following the constitution have no where to go on TV. So, they get their "news" from the Internet instead, and avoid the cable "news" propaganda channels that are little more than mouthpieces for rich "elites" running the two-party system.