Facebook's Latest Design Was So Good It Failed
 

How can anything be "so good it failed?" Then again, this is Facebook we are talking about, why am I even asking that question? After an investigation into the problem by Facebook's data team, they discovered that the new News Feed was performing too well. It was performing so well from a design standpoint that users no longer felt the need to browse areas outside of the News Feed as often, so they were spending less time on the site. Unfortunately, this change in user behavior led to fewer advertisement impressions, which led, ultimately, to less revenue.

http://www.hardocp.com/news/2014/03/...o_good_failed/