...political activist Eli Pariser told the Technology Entertainment and Design conference on Wednesday, the internet has quickly encased us in personalization bubbles where increasingly the only people and ideas we encounter are the ones we already know.
...
Take his Facebook page, for example. Pariser used to receive comments and links from readers on both sides of the political spectrum. Then one day he noticed his conservative friends had disappeared; only links from his liberal friends remained. Facebook, without asking him, had seen that he clicked more often on links from left-leaning friends and simply edited out the rest using an algorithm which hides from view the kinds of content, by past behavior, it has determined you are less likely to interact with.