"Even if you apply [that 90 percent of everything is crud], that still means the App Store has 5,000 good apps, which is about 4,900 or so more than anyone will ever need," Gartenberg says.

And Apple has used those good apps to its advantage, making them the centerpiece of its TV advertising for the iPhone. You can't watch television for long these days without coming across a 30-second spot advertising that "there's an app for that."

Current Analysis' Greengart says that the TV commercials has succeeded in convincing consumers that buying a smartphone means considering the applications that support it. And that's good news for Apple as the iPhone faces stepped-up competition from the Palm Pre, BlackBerry Bold, and a host of Android OS-based devices.

"It is no longer enough to match the iPhone's user interface and media capabilities," Greengart said. "Now you need to compete with 50,000 applications."

To be sure, the App Store faces some challenges in the near future. As the number of apps swells, it's going to be harder for consumers to find programs as well as for app makers to get the word out about their software. "The sheer breadth of options on the App Store will become its own challenge," Greengart said.