Android apps purchased from Amazon will work on multiple devices, use Amazon DRM
Android applications purchased in Amazon's app store (which may finally go live to consumers any time now) will use Amazon's special sauce of digital locker/digital rights management to help combat piracy. Amazon spells it out in its developer blog:
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Customers who purchase an app will retain an entitlement to their app even if they decide to replace their current Android device and/or purchase new devices, as long as the new devices meet the installation requirements of the app. This provides insurance to customers that their purchased apps will be available for use on all supported devices, even if the customer has uninstalled or otherwise removed those apps in the past.