Apple's App Store attracted thousands of developers and boasts hundreds of thousands of apps. While most other platforms have been less successful with central app repositories, Android is the only other platform really vying for the attention of developers. Several recent reports suggest interest in Android among developers is growing significantly, while interest in BlackBerry, Palm, Symbian, and Windows Mobile continues to erode.

In a recent report from VisionMobile, analyst Andreas Constantinou notes that while smartphone platforms like Symbian and BlackBerry have more market share by units sold, both iOS and Android are commanding the most mindshare. "For example," wrote Constantinou, "the Symbian operating system is deployed in around 390 million handsets (Q2 2010), and claims over 6,000 apps, while Apple's iPhone has seen 30x more applications while being deployed at just 60 million units over the same period."

This same conclusion is supported by the results of a mobile developer survey last month from Appcelerator. iOS and Android development attracts the attention of a majority of mobile developers by a wide margin. All the while, interest in Windows Mobile and BlackBerry platforms is dropping, despite both platforms having a strong share among business users.

Besides the hype that both platforms generate, the incentive for most developers is money. Apple and Android consistently show sizable growth via a variety of metrics, including unit sales and online use.

Both platforms have app stores that offer quicker time to market and quicker time to payment. VisionMobile reports that app stores (i.e., Apple, Android) generally make apps available in about 22 days as opposed to 68 days for mobile operators, and offer the first payment in about a month versus two or more months compared to offering apps via mobile operators.

And just as important, both platforms have growing user bases that frequently use their respective app stores and spend money on apps. While Apple often boasts of the number of apps sold through the App Store—the most recent count last month was 5 billion apps downloaded in just two years—VisionMobile says that just 10 percent of Windows Mobile users use its Windows Marketplace for Mobile to get apps. Appcelerator also says that a large majority of developers see Apple's App Store as offering the best commerce capability, best app discoverability, and largest addressable market for consumer and business apps.

Appcelerator's report offers some interesting insight that shows developers favoring iOS in the short term, but leaning towards Android for long-term development prospects. Developers overall feel that the best devices run iOS, and along with its App Store advantage, 78 percent of developers said iOS offers the "best near-term outlook." However, developers see Android as having the most capabilities and being more open. A 54 percent majority believe Google offers the "best long-term outlook."

Recent analysis by AppStore HQ also shows many developers, especially larger ones with more resources available for porting existing iPhone apps, increasingly adding Android apps to their stable. While AppStore HQ's numbers still show a large majority of developers favoring iOS over Android (about four to one), nearly 1,500 of those registered developers have both iPhone and Android apps. These are mostly larger media companies and developers, such as Facebook, Gameloft, Amazon, Intuit, and others, but as Android rises in popularity, the economics will begin to favor smaller developers as well.

The iOS platform is well established and has attracted tons of developer attention. The launch of the iPad has fueled further interest, but the iPad's early success is also garnering more interest in Android-based tablets. Along with the maturing feature set available in Android 2.2, and hints of future improvement in 3.0, there's a lot for developers to like. With Nokia fragmenting its approach between Symbian and MeeGo, Microsoft scurrying to get Windows Phone 7 to market, RIM having offered little new with BlackBerry OS, and HP and Palm having little to say about webOS, that leaves the door wide open for iOS and Android to dominate.

HTML5, CSS3, and JavaScript are beginning to be used to make cross-platform Web apps that can supplant the capabilities of native apps. However, until there is a foolproof way for developers to monetize them—a Web app store, perhaps—expect developers to continue to pursue native development for the foreseeable future.