Book About how Blogs Tend to Radicalize our opinions

There was a Story in NYMag about Obama Courting outside opinions, and there is this book that was referenced.

Going to Extremes: How Like Minds Unite and Divide

I keep wondering how, over time we as traders may realize that the blogging is creating more of a "Bubble Mentatlity" or a "Legion of Lemmings"

Cass R. Sunstein, the Harvard law professor and Obama’s recently appointed regulatory czar, has a book coming out that sheds light on the virtues of open-mindedness. In Going to Extremes: How Like Minds Unite and Divide, Sunstein argues that spending too much time in the company of like-minded people serves only to exaggerate your own views and make you less tolerant of differing opinions......

From this perspective, the excesses of Obama’s predecessor make chilling sense. George W. Bush famously lived in a bubble, and Sunstein’s point is that bubbles don’t just insulate; they radicalize. From this comes the uttering of such sentences as “We create our own reality.”
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I asked Obama whether he read Daily Kos and other liberal blogs. “One good test as to whether folks are doing interesting work is, ‘Can they surprise me?’ ” he replied. “And increasingly, when I read Daily Kos, it doesn’t surprise me.”
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Toward the end of Annie Hall, Woody Allen spies a copy of National Review in Annie’s apartment and demands to know what it’s doing there. “Well, I like to get all points of view,” she protests.