App stores, which were almost unknown thing just around three years back, are now a big battlefield for platform owners, app developers and third parties such as Amazon.

Online retailer Amazon recently introduced its own Appstore, providing Android users with one more option to buy apps from, while software giant Microsoft blew its own horn claiming that its Windows Phone 7 app toolkit had that far been downloaded by more than 1.5 million times. It may be noted here that Microsoft’s Windows Phone 7 app toolkit allows developers to create apps for the relatively new platform.

According to Microsoft’s claims, Windows marketplace now has as many as 11,500 apps, 7,500 of which are paid apps, while 1,100 apps are being used by the software company to generate revenue from in-app ads.

Google’s Android Market boasts of its more than 150,000 apps. But, the leader of the market is still Apple’s App Store, which boasts of more than 350,000 apps.

Apple, which started it App Store, has been whole-heartily challenging anyone who is using the term "App Store”, claiming it acquired the exclusive right to use the term.