from the google play developer guidelines: "Developers offering additional content, services or functionality within another category of app downloaded from Go

from the google play developer guidelines: "Developers offering additional content, services or functionality within another category of app downloaded from Google Play must use Google Play's in-app billing service as the method of payment, except ... where payment is for digital content or goods that may be consumed outside of the application itself (e.g. buying songs that can be played on other music players)." the kindle store is kind of straddling the line between affected and unaffected. if reading a kindle book on an e-ink kindle device counts as outside the app, they're fine. I'm guessing google will give amazon a pass here, the regulation is clearly meant to stop games with scammy IAP, not ebookstores.