Since we launched the new profile, we've been looking closely at how we can continue to improve Feed and Feed stories, in order to encourage more actions for your applications and your users. Today we're launching a new feature to add greater engagement to your Feed stories: action links.
An action link is a call to action for the user to take within your application, directly from a Feed story. For example, it could be a call to buy an album or a book, or write a review. The URL encoded within the action link takes the user to the appropriate place to perform the action.
Action links appear next to the "Comment" link you see on Feed stories today. For technical details and more information, see the Facebook Developer Wiki.