When a Facebook user reads an article on a site, which has implemented the Recommendations Bar, a small pop-up window appears at the lower right corner of your screen. It suggests more articles and prompts you to 'like' them. Once you hit the Like button, the story gets published on your timeline and will appear in your friends' news feed.
The main idea is to narrow down searches making them more relevant to a reader. Facebook developer Jeffrey Spehar's post on the company's developer page says," Recommendations are based on content that friends have explicitly liked and shared in your app or website."
The plug-in has been tested with sites like Mashable, Wetpaint and The Mirror. Facebook findings reveal that sites saw 3x their normal click through rate on stories suggested by the bar than through the Recommendations box. Sites can get the feature with a few lines of code or as part of the Facebook for Wordpress plug-in.
Click here for instructions on how to set it up.