One Place to Start

How do we find those places where the rivers run in two directions? One clue is on Amazon.com, where readers of divergent political persuasions find books in common, then branch off. See John Udell's Weblog at the Link below.

Turns out there are certain titles widely read by liberals and conservatives, such as Bush At War. But after that, "Customers who viewed this book also viewed" head off in opposite directions.