Polarization of political reading

Valdis Krebs uses data from Amazon to chart networks of people who read political books. Two groups typically emerge from the data: people who read liberally oriented books and people who read conservatively oriented books with a couple of books that both groups read. He ran his analysis again a few days ago and found not two groups but three — roughly: 1) pro-Obama, 2) anti-Bush, and 3) conservative — and no books that the groups read in common. (via big sort)

• books
• politics
• social networks