One More Reason Why You Want to Acquire Email Addresses and not Facebook Likes
Facebook has changed the way pages interact with their fans. The site is now reining in the visibility of each page's post among its audience of fans, and encouraging the use of promoted posts to reach them. This is after its push to marketers to try Facebook ads in order to acquire fans. The result of Facebook's closed messaging system is an audience marketers pay to acquire and then pay to reach.
Read more at the Deliverability.com blog.