DIVIDED AMERICA: Constructing our own intellectual ghettos

In this world of hundreds of channels and uncounted websites, of exquisitely targeted advertising and unbridled social media, it is easy to construct your own intellectual ghetto, however damaging that might be to the ideal of the free exchange of ideas.
"Right now the left plays to the left and the right plays to the right... That's why we keep ratcheting up the heat. We're throwing red meat. We're in a room that is an echo chamber, and everybody's cheering."...
in "Going to Extremes: How Like Minds Unite and Divide," Harvard University's Cass Sunstein argued that when like-minded people gather in groups, they tend to become more extreme in their views.