With so much information available on the internet, many people stick to websites they agree with. Liberals tend to read liberal blogs, and conservatives read conservative ones. Techies interact with other techies, and artists with other artists. If you want to see the new Michael Moore movie, Amazon.com or Netflix can suggest dozens of other anti-war, anti-corporate films. People can spend a lifetime surfing the web, and never have to confront a dissenting point of view.
This kind of filtering and self-selecting isn’t new, but it’s getting more extreme. “As a result of the Internet,” University of Chicago professor Cass R. Sunstein writes for the Chronicle of Higher Education, “we live increasingly in an era of enclaves and niches — much of it voluntary, much of it produced by those who think they know, and often do know, what we're likely to like.” These niches reinforce similar points of view, creating what Sunstein calls “enclave extremism.”
Extremism isn’t always a bad thing, according to Sunstein. Abolitionists and civil-rights activists were extremists in their time. Problems arise when the reinforced point of view is wrong. Global-warming deniers can find plenty of “evidence” on the internet that environmentalism is a fraud. Sunstein writes that a lack of dissent can also lead to “mutual suspicion, unjustified rage, and social fragmentation” if left unchecked.