Andrew Sullivan, about as popular a blogger as you'll find, had 11,000,000 page views in January (9 million the previous month). Page views aren't people, of course, but even if they were that comes out to about 350,000 a day. Let's say, by approximation, 0.1% of the American population (not to mention that some of his readers aren't Americans). This means, to put it mildly, that most people don't read Andrew. I'll go out on a limb here and say, most people have never heard of Andrew. And he's one of the biggest around, I repeat.
For all the self congratulatory stuff bloggers like to write about the demise of the mainstream media and all that, maybe the case isn't sealed yet.