Facebook yesterday unveiled its Recommendations Bar social plug-in, which allows website visitors to like content, get recommendations, and share what they’re reading with friends. The Recommendations Bar is docked to the lower right or left of the a website's screen. When the page loads the Recommendations bar will be collapsed and the user will have the option to 'like' your page.
The Recommendation Bar is another option for websites (particularly blogs and media sites) to introduce social elements and benefit from referral traffic, described Mashable.
True, Facebook already had a Recommendations Box plug-in, but as HubSpot describes, the Bar is better for marketing. The Box simply allowed users to check out other articles or content on your website, with no opportunity to share content. The Recommendations Bar does just that, motivating sharing action among website visitors, and giving them more opportunities to 'Like' the content on a page and therefore, share it with their Facebook connections.