http://fortune.com/2015/11/09/facebook-media/
“Some publishers have seen traffic from Facebook plummet by 40%, which reinforces the risks of handing control over your audience to the social network.”
“…This creates a number of potential issues, including the fact that a surprisingly large proportion of Facebook users are apparently unaware that the social network filters what they see and when they see it. Facebook also routinely censors news for a number of reasons, which is (or should be) problematic for media companies who are entering into a close relationship with the company. And yet, it has such a massive amount of reach that publishers of all kinds have to use it, whether they want to or not.”