Amazon has a new Kindle Countdown Deals Page.
From reports it sounds like the page is supposed to tell you how long until the book is no longer on sale. But that does not seem to be the case.
Instead it is just showing the book that are on sale.
This seems to be trying complete (in combination with changes to the wishlist) sites like ereaderiq.com and jungle-search.com that highlight sales or search for price drops. Those external sites get a commission from links and if Amazon can move those users to Amazon generated deals then Amazon get more profit per sale.
But this Kindle Countdown Deals is only open to Kindle Direct Publishers. So you have to have an agreement to only sell ebook through Amazon to be on this page (although I would not be surprised later if publishers negotiated directly with Amazon to be on the page.)
Right now there are 79 books on sale all for $0.99.