Summary
In Google’s Play Store, there are no Amazon’s apps, although there are used to. This is a punishment for Amazon by Google, and the reason is Amazon’s new app system which makes it possible to download various apps in Amazon’s app, without Google’s Play store.

Reaction
This passage mentions the possibility of Google’s monopolization in apps’ market. It is very hard for Amazon to sell their apps by itself, if Google could change the system of Google Play and eliminate Amazon’s app.
I searched what occurred after this incident. 1 week later from the incident, for instance, Amazon’s apps revived in Google Play. However, in the main app of Amazon, there is no system to download apps on its own. Because Amazon’s own downloading system looks infringing Google Play, Google removed Amazon’s apps from Google Play.
In the apps’ market, Google and Apple work hard to get customers. Amazon is new company to take in to their fight. In truth, the app store popularity of Google Play is about four times higher than Amazon (Figure1). But for instance, many users of Google Play download only free apps. Google gets very many customers; however, Google get little revenue from their downloading (Figure2).
In conclusion, Google struggled to make profit from Google play, so they could not allow Amazon who had high revenue rate from apps to leave from Google Play and Amazon had no technology to leave perfectly from it.

Figure1(from http://www.androidpit.fr/google-play-store-apple-app-store-amazon-app-shop-rapporte-plus)

Figure2(from http://www.webpronews.com/amazon-appstore-generates-far-more-revenue-than-than-google-play-2012-03)

I’m so sorry about no detail of these sites and use figures without any permission…