It faced down long-established booksellers in 1994, expanded that fight to big box retailers a few years later - and, in 2011, it took on Apple and Google with the launch of the Kindle Fire tablet. Now it has its eye on the mobile gaming market - and to win this fight, it will need to take its gloves off.

The Kindle Fire is already a decent gaming device. 70% of all users play games on it - with ARPU's that are higher than Google Play and neck-to-neck with Apple. But there's room to grow. And while Amazon might be behind to the gaming world, Microsoft was also a latecomer in the console space - and it went on to be a leader.