Marketers have been using Like Gating and Fan Gating on apps for years. It's the ability to gate content so that a visitor must become a fan in order to access the content. Today, November 5, 2014, Facebook ended that. It's now against Facebook policy to require a "Like" to gain access to content or deals, and it's been removed from the Facebook API.
Read more: http://mikegingerich.com/facebook-cha...