Manipulated news feeds

In January 2012, for one week, Facebook manipulated the news feeds of more than a half a million users to see how postings that were being shown in the news feed effects the types of posts the users themselves would post after viewing them.  The results were published this month in the academic journal, Proceedings of the National Academy of Science.  The findings show users who saw more negative content were more likely to create their own negative posts.  Users who viewed more positive content were more likely to create positive posts.  In response to the many upset users of the site, Facebook Data Scientist, Adam Kramer:

The goal of all of our research at Facebook is to learn how to provide a better service.  Having written and designed this experiment myself, I can tell you that our goal was never to upset anyone.