iPhone owns 51% of US smartphone traffic

The ad company's latest Mobile Metrics report, which tracks handheld web traffic based on served banner and text ads, gives the iPhone a majority 51 percent share of smartphone requests handled in the United States despite the Apple device's official limitation to a single carrier.

In view of the entire U.S. handset market, of which smartphones represent a smaller growing sector, Apple devices left their competitors behind and trumped Motorola by almost 10 percent.

The iPhone maker was the only firm to post a percentage gain greater than a half-point, and ultimately saw 6 percent growth where most stayed near-flat or declined. A breakdown by each particular device shows the iPhone making almost 17 percent of all mobile web requests in the United States, while the iPod touch requested a still-large 12.3 percent.

That means the iPod touch, likely reflecting the holiday season's record sales of iPods, upped its market share by 5.2 percent in January, besting all others by almost 5 percentage points.

Apple's 18.3 percent of worldwide ad requests by company came in second to Nokia's 30.1 percent. However, the number is more a product of the large range of models sold by the Finnish manufacturer, which claims 9 different units on the leaderboard. When individual models from all makers compete against one another, the Nokia advantage is split nine different ways, allowing the iPhone and iPod touch to more easily come in first and second respectively.

The closest competitor is Motorola's veteran RAZR V3, whose three percent of worldwide traffic was a fraction of that for both the iPhone (11 percent) and iPod touch (7.4 percent). The Nokia N70 was fourth, at 2.5 percent.

Again limiting attention to smartphones alone, the iPhone has already grabbed nearly a third of the worldwide smartphone market at 32 percent. This comes as its international rollout is still underway and not yet completed, while Motorola and Nokia already have much larger distribution.