New research by Feng Zhu and colleagues reveals why sometimes it's better for fierce competitors like Apple and Amazon to work together L et's get one thing straight from the start: Apple and Amazon are not friends. If they were high school students, they'd be mean girls glaring at each other from opposite sides of the cafeteria, jealously forcing their friends to pick sides between Team Chloe and Team Madison. To put it into market terms, both companies would like nothing better than to have customers to themselves, wrapped up in their own seamless media universes: iTunes, iPad, and Apple TV on the one hand; and Kindle, Amazon Prime, and Fire TV on the other. So why would Amazon release a version of its Kindle Reader on Apple's iPad, allowing users to access its library of exclusive digital books? "Doesn't that diminish interest in the Kindle device?" asks Feng Zhu, an assistant professor in the Technology and Operations Management unit at Har...