RRL Facebook/Twitter

#1
So I was scrolling down the front page and something strange caught my attention. At first, I thought it was some kind of ad because I saw the cover of my book on the page linking to facebook and twitter. I clicked out of curiosity and to my surprise, I saw that my book was actually posted on both of the pages a few days ago. I was wondering if anybody knew how books were picked out for that? Is it as simple as luck of the draw or did somebody working the site actually like it that much?
If you're into dark, low fantasy check out my book: Wings of Sorrow