It happens all the time in retail shops—a customer picks up an item, wanders around, returns the item to the store shelf, and leaves the store without purchasing a thing. In the world of online retailing, a whole “cart” of merchandise is regularly left behind, more often than a sale is actually made. That’s right, according to multiple studies, online retailers commonly have over 50 percent of their customers load up their carts and never actually check out. If half the customers in y