Update: as of November 2011, our Android version of the app outsells iOS version of the app.
Since our release of MobileNoter SE into Amazon Appstore two months ago, our sales have been growing steadily, but one thing remains the same: Google Android market outsells Amazon Appstore by 10 times. In other words, an application that brings $10K of monthly sales in Google market will sell for a total of $1K in Amazon market.
The ratio is pretty accurate, because we sell exactly the same application, and we don’t have any marketing or PR targeting specifically any of the markets.
And from the Captain Obvious department: both of these markets, even combined, are still being dwarfed by the Apple AppStore sales.