Indeed, other smartphone players have decided that they wouldn't mind an App Store of their own. As Gartenberg notes, Google, Palm, Research In Motion, and Nokia have all opened mobile application stores, with Vodafone and Microsoft planning efforts of their own. The App Store "has made everyone else scramble," Gartenberg said.

Those companies will have a hard time matching Apple's success. The App Store has thrived because, unlike many of the mobile software retail efforts that already existed, it delivered convenience to end users and app makers alike.

"Apple's App Store is successful not just because it is easy to browse but because of the processes underlying it," said Avi Greengart, research director for consumer devices at . "Developers know how to get to market and how much they will get paid, while consumers know there is a single place to obtain applications and a simple purchasing experience."

Gartenberg agrees: "None of the other platform providers had ever taken the step of connecting users to third-party applications and showing what they can do."

It helps that software makers have stocked the App Store with an impressive array of applications, everything from productivity boosters to games that rival what you'd see on a dedicated handheld gaming console. Critics of the App Store often cite the plethora of disposable 99-cent novelties--noisemakers, quizzes, and other diversions--but that ignores the significant portion of apps that actually extend the capabilities of the iPhone and iPod.