The wizards of apps

(Fortune Magazine) -- After six months in development, Zillow's new iPhone application - a data-intensive program that marries the gadget's GPS functionality with the real estate site's property-value estimates, or Zestimates - was finally ready for the light of day.

CEO Richard Barton considered the app nothing less than a relaunch of his company. So naturally he didn't want it to disappear into the sea of 35,000 programs in Apple's App Store. A well-connected Zillow board member secured a meeting at Apple for Barton and president Lloyd Frink. And then the duo, who toiled a combined 28 years at Microsoft (MSFT, Fortune 500), hopped a plane from Seattle for Cupertino to kiss a few rings - in hopes of elevating their app to What's Hot or New and Noteworthy status in the App Store.

"It's ironic that one guy who started at Microsoft in the '70s, and me, an old Microsoft guy too, would be making a trip to the Infinite Loop," says Barton, referring to the address of Apple's HQ. "But when someone is potentially going to be your most important partner, you want to get to know them."

That's not the only irony in play here. For Zillow and hundreds of other web developers, the rise of the App Store - as well as the proliferation of competing wireless platforms such as Google's (GOOG, Fortune 500) Android, BlackBerry's App World, and forthcoming stores from Palm and Nokia (NOK) - feels oddly retro. A decade after the web emerged as a unified platform for delivering rich content, the mobile web has become a series of proprietary systems. Developing a mobile play means refitting sites for a small screen, customizing to individual peculiarities, and redoing the process for each platform.

But businesses ignore the wireless web at their peril. In less than a year, downloadable wireless apps have become the place to be for online vendors, games, and content creators. And the influence of apps is sure to grow. According to the Pew Foundation's recent study "The Future of the Internet III," mobile devices will surpass computers as the primary tool for Internet connectivity by 2020.

Apple, whose iPhone customers have downloaded a staggering 1 billion apps since last July, is clearly driving the trend. It wasn't long ago that the company's developer-relations staff was begging software publishers to build Mac apps. Lately, however, the power compass has found a new magnetic north.

The App Store - an iTunes Store for applications - has turned the device into a moneymaking platform for big businesses and indie developers alike. Pandora, an Internet radio company whose app has remained among the most popular since July, has been revitalized. "It's been a game changer for us," says founder Tim Westergren. "We're getting 30,000 new iPhone listeners a day, and 60,000 overall.

All that activity, not to mention ubiquitous iPhone commercials, has developers clamoring to get into the App Store. Only problem: Like the talent agent with a star client, Apple (AAPL, Fortune 500) seems in no rush to communicate with developers. The company claims that 98% of apps are reviewed within seven days, but many developers gripe that the review process vacillates between opaque and capricious. The only thing worse than an unexplained rejection is a months-long purgatory of nonapproval/nondenial.

Even the most successful developers acknowledge that Apple can be frustrating. Aaron Patzer, founder and CEO of finance site Mint.com, says his team launched an app last November. Today iPhone owners visit Mint 1.2 times a day on average, vs. twice a week for web users. Apple has spotlighted Mint in commercials. Naturally Patzer gushes about his relationship with the company. But he also remembers what it's like to be just another developer. "We literally found out that our app was approved because we saw it appear in the App Store," he says.

So how to catch Apple's attention? Developers suggest designing a must-have app for users, not for Apple. Great apps have a way of bubbling up, and when they do, Apple will take notice. Even Zillow's experience reflects that. In its first day Barton's app was downloaded 16,000 times and climbed the real estate and lifestyle charts entirely on its merits - without What's Hot or New and Noteworthy status. No ring kissing necessary.