By now everyone's heard of the investigation into Facebook's curation of the news, kicked off by this Gizmodo article reporting that Facebook employees routinely suppressed conservative news.
The "filter bubble" should be a real concern as the web becomes more personalized (and increasingly, the web is where we'll spend more and more of our time). Eli Pariser has a great TED Talk about this, from 2011:
Here's more on WSJ's methodology.
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