Fewer people than you might guess:
[T]hose who blame Fox and MSNBC for dividing the country should check their sums. Markus Prior of Princeton University has dug into data, much of it unpublished, from ratings companies who remotely track viewing habits in sample households. His conclusion is that Americans fib about what they watch, and that large majorities simply shun cable news. Perhaps 10-15% of the voting-age population watch more than 10 minutes of cable news a day, a share that rises modestly before exciting elections. For most individual news shows (including hybrids like Jon Stewart’s satirical “Daily Show”), 2m viewers counts as a wild success. That is the equivalent of 0.8% of voting-age Americans.
Yes, but I also think that is too narrow a definition of influence. If the 10 – 15 percent form the bedrock of one party’s base, and shape and echo a message fed through the hyper-partisan cable pipeline, it is precisely the isolated nature of the phenomenon that gives it power. After all, anyone who is not super-ideologically committed or highly partisan would find both MSNBC and Fox to be ridiculous, propagandistic caricatures of news. That’s why their audiences are relatively small. In fact, both propaganda channels may have maxed out on their reach because most (sane) Americans never stop laughing or gasping at cable news’ inane extremism when they have the misfortune to turn it on. But keep that audience geographically isolated, feed them with all sorts of political, erogenous-zone pap, and get them to spread the word (far more credibly than the TV) and you have a political movement. Without Fox News, no Tea Party.
Cable news is both a marginal enterprise and yet a central force behind the disintegration of a reasonable national conversation. It’s tiny in size but exponentially more potent in influence. Which makes it a particularly vexing problem for a politically stale-mated country.