Barnes & Noble sued Amazon on May 12, 1997, alleging that Amazon's claim to be "the world's largest bookstore" was false because it "...isn't a bookstore at all. It's a book broker." The suit was later settled out of court and Amazon continued to make the same claim. Walmart sued Amazon on October 16, 1998, alleging that Amazon had stolen Walmart's trade secrets by hiring former Walmart executives. Although this suit was also settled out of court, it caused Amazon to implement internal restrictions and the reassignment of the former Walmart executives.
The Amazon sales rank (ASR) provides an indication of the popularity of a product sold on any Amazon locale. It is a relative indicator of popularity that is updated hourly. Effectively, it is a "best sellers list" for the millions of products stocked by Amazon. While the ASR has no direct effect on the sales of a product, it is used by Amazon to determine which products to include in its bestsellers lists. Products that appear in these lists enjoy additional exposure on the Amazon website and this may lead to an increase in sales. In particular, products that experience large jumps (up or down) in their sales ranks may be included within Amazon's lists of "movers and shakers"; such a listing provides additional exposure that might lead to an increase in sales. For competitive reasons, Amazon does not release actual sales figures to the public. However, Amazon has now begun to release point of sale data via the Nielsen BookScan service to verified authors. While the ASR has been the source of much speculation by publishers, manufacturers, and marketers, Amazon itself does not release the details of its sales rank calculation algorithm. Some companies have analyzed Amazon sales data to generate sales estimates based on the ASR, though Amazon states:
Bezos and those he’s hired over the years have been prescient about a vast number of shifts in how people spend money, buy products, and use the internet. But none of their predictions may have panned out quite as lucratively as Amazon Web Services, the company’s cloud computing division that loans server space and other computing resources at massive profit margins.