The problem is that when large blogs become A-list they often outsource their writing and "voice." They still get high traffic but lose the personal sense of trust and consistent viewpoint on the industry of which they are focussed. This makes the medium-sized blogs the most infulential in changing ideas.
I have heard of this book several times but never realized that Buffet was the person who made it so popular. He's got to be the most powerful person to ever come out of Nebraska.