Without a doubt, the highest-profile part of a smartphone is the hardware -- the user interface and the powerful engine within. The real drivers of the new world of super-powerful phones are the applications. In many ways, the way in which these apps are being distributed is as unique as the devices themselves.

Insight Research Corporation this week released a report that shows just how pivotal these apps – more specifically, several relatively narrow types – will be. The report, The Mobile Phone and Financial Applications Worldwide, 2009-2014, says eight types of financial apps will be downloaded by 2.2 billion people and generate $124 billion for carriers and developers during the next five years. The apps, the report says, are in mobile banking, mobile gaming, mobile gambling, mobile stock trading, mobile proximity and retail, mobile credit cards, mobile bar coding and mobile peer-to-peer.

The major way in which these applications are distributed, application stores, is becoming a key smartphone battleground. Apple, of course, has led the way with the App Store. On April 23. Venture Beat and others reported that the App Store downloaded the its billionth app. The piece said that to reach that mark the company averaged 3.5 million downloads daily since its launch on July 10 of last year. All told, Apple device owners average 33 applications each.

Of course, the App store isn’t the only game in cyber town. There is the BlackBerry App World and the Android App Store, for instance. mocoNews.net reports that Handmark has unveiled the Mobile Store Platform, which will enable others to launch app stores using the company’s content. Handmark will join at least two other providers, GetJar and Handango, as providers not tied to specific operating systems. Handmark will launch with applications for Windows Mobile devices and expand later. In March, Handango launched the App Store Accelerator and said that it being used – the story doesn’t specify in precisely what way – by BestBuy and Verizon Wireless. Last year, GetJar told mocoNews that it is working with more than 10 carriers worldwide.

This long Fast Company piece does a good job of explaining what is happening – Apple led, others follow – and providing a sense of how influential application stores are likely to become. The reality is that so many people can't download so many applications without fundamentally changing some industries. The example the writer uses is potent: ShopSavvy takes a picture the shopper takes of a bar code of a product he or she is considering and instantaneously display where the item can be found cheaper, both online and off. Indeed, the bottom line of the piece seems to be that while the vast majority of people are obsessing over the evolution of the iPhone and other smartphones, the winners and losers may in good part be determined by which organizations run the best application stores. As it does with the hardware, Apple enjoys a big lead.

The application stores are big business, and clearly have to find their footing. During the same week that the App Store downloaded its billionth app, it was forced to withdraw an odious app called “Baby Shaker,” in which the user is encouraged to shake the device until the audio of a baby crying stops and red Xs appear on the infant’s eyes. Commentators wondered how such an applications could be approved, while at least one, Saul Hansell of The New York Times, questioned the extent of the App Stores’ responsibilities or even right to control the content it carriers.