Use this tags for questions concerning the Amazon Appstore, a mobile application store for Android, one of the 'alternative-markets' to the 'google-play-store'
What is the "Amazon Appstore"?
In March 2011, Amazon opened its mobile app store. The kindle-fire was released about half a year later (September 2011). Though running Android, this device relies solely on the Amazon Appstore for its marketplace, as it was designed for media consumption in the Amazon ecosystem. The Amazon Appstore is in no way tied to the Google Playstore, but rather acts as a direct competitor.
Where should I use this tag?
Whenever your question is directly related to the Amazon Appstore, of course. If you rather want to use a different "source" on your Kindle, either use the google-play-store tag (if that is your goal), or refer to the alternative-markets tag wiki for related tags to other sources.