http://www.jonloomer.com/2014/08/11/facebook-like-gating/ http://www.easypromosapp.com/blog/en/2014/09/facebook-eliminates-the-obligation-for-a-user-to-become-a-fan-of-a-page-what-this-means-and-what-you-need-to-know-for-your-campaigns/
