Facebook has instituted a new policy whereby page owners may not accept payment for sharing content (videos, articles, etc.) that they did not have a hand in creating.
What this means is that people such as George Takei, who have very large Facebook followings, cannot post articles on their page and accept payment for said posts.
The reason this business model existed in the first place was that site owners found they could arbitrage the cost of the paid post traffic and get higher revenues from the surfers landing on their sites and generating ad revenue. Some sites were able to purchase visitors from these posts from as low as $0.01, much lower than the cost to buy them directly from Facebook itself (which made them understandably not happy).