The iPhone Colorsplash app has been in the top 50 downloads since its release in February. (Apple)

A Vancouver programmer has had cause to celebrate as the hugely popular iPhone passed a major milestone last month — the two-billionth download of an iPhone app.

Apple says the company has sold about 50 million iPhones around the world since they were launched more than two years ago and their users have downloaded about 4.5 million iPhone programs, known as apps, per day since July 2008 when Canadians got the iPhone — the second generation iPhone 3G.

And that's meant big profits for programmers such as UBC graduate student Hendrick Kueck, who spent his free time creating an application called ColorSplash that lets people play with the colour in their digital photos.

"What the application does is loads up the image and then converts it to black and white. You can use your finger on the screen to paint back the original colour of the image."

The program, which iPhone owners can download to their phone for $1.99, got a big boost after it was featured on a popular Mac blog the day after its launch. Since then ColorSplash has been in the top 50 iPhone downloads, and even reached the No. 3 spot on the sales chart.

Kueck won't say how much money he has made, but under Apple's standard agreement, he would keep 70 per cent of all sales revenue. And ColorSplash was not his first hit. He already had one mildly successful app, called Juxtaposer.

Another example of a wildly successful app is iFart. The digital whoopee cushion reached No. 1 on the sales chart, raking in a reported $40,000 in just two days last Christmas, at $0.99 per download.

Most apps not money-makers

Numbers like those have triggered a gold rush mentality among programmers, said Parveen Kaler, the first instructor to teach an iPhone app development course at the B.C. Institute of Technology.

Kaler says novelty items like iFart were successful at first, but now consumers are more discerning about where they spend their money.

Kaler compares the App gold rush to the tech stock bubble of 10 years ago and says companies that set up shop to develop only iPhone apps are struggling. He says smart companies are using iPhone apps as one part of their business — not the sole focus.

"There are about 80,000 different applications on the iTunes store, and I would say the top 100 in each category generate revenue. Everyone else is struggling," Kaler said.

Kueck agrees getting a big payout from a new app is difficult because a good idea represents only a very small piece of a successful app.

The most important element is a user-friendly interface, which is far more time-consuming and difficult to produce than it looks, said Kueck.