"Preorder buttons" refer to buttons or links on a website or online store that allow customers to reserve or purchase a product before it is officially released or made available. Full definition
Amazon wields these tools as leverage for the same reason they removed preorder buttons for Hachette authors. (huffingtonpost.com)
The latest news is that Amazon offered to pay Hachette authors their regular royalty rate, reinstate preorder buttons, stock Hachette titles, and then give everything left over to a literacy charity. (jakonrath.blogspot.ru)
The same goes for Amazon's subscription products, preorder buttons and numerous other innovations designed to increase the value of an order and the total lifetime value of its customers. (entrepreneur.com)