From the amazon page for this book: What do customers ultimately buy after viewing this item? 91% buy the item featured on this page | 6% buy Dreaming in Code

From the amazon page for this book: What do customers ultimately buy after viewing this item? 91% buy the item featured on this page | 6% buy Dreaming in Code... | 1% buy Made to Stick: Why Some Ideas Survive... | 1% buy Harry Potter and the Deathly Hallows (Book 7) by J. K. Rowling What could it mean? :)