“Specifically, Goodreads finds two requirements of Amazon’s API licensing agreement too restrictive. Amazon requires sites that use its API to link that content back to the Amazon site exclusively—so a book page on Goodreads would have to link only to its product page on Amazon, and not to any other source or retailer. Goodreads links to many online retailers. “Our goal is to be an open place for all readers to discover and buy books from all retailers, both online and offline,” the company told me. Amazon also does not allow any content from its API to be used on mobile sites and apps.”