“It is well known that when like-minded people get together, they tend to end up thinking a more extreme version of what they thought before they started to talk. The same kind of echo-chamber effect can happen as people get news from various media. Liberals viewing MSNBC or reading left-of-center blogs may well end up embracing liberal talking points even more firmly; conservative fans of Fox News may well react in similar fashion on the right.” — “Breaking Up the Echo,” Cass Sunstein, September 17, 2012.