It's been on the market for just six months, and already the iPhone (plus its Wi-Fi-only variant, the iPod Touch) is the most used mobile browser for Internet access in the U.S., according to Irish researcher StatCounter. At No. 2 is the Symbian OS used in Nokia's devices. Globally, the two positions are reversed. In either case, Windows Mobile -- in all its versions -- is just a blip.

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As of March, the iPhone and iPod Touch account for 0.23 percent of U.S. Web traffic, while the business-friendly Symbian-based Nokia devices come in second place, though StatCounter did not provide their traffic percentage. Globally, Nokia comes in tops at 0.25 percent and the iPhone and iPod Touch second at 0.08 percent, despite its availability in just a few countries.

Another researcher, Net Applications, puts the iPhone/iPod Touch in top position with 0.19 percent of global Web traffic, versus 0.06 percent for all Windows Mobile devices. (Net Applications doesn't count the Nokia platform traffic.) When looking at browser traffic, Net Applications rolls together the iPhone's Safari and the desktop version, not as separate apps. Microsoft's Pocket Internet Explorer browser claims 0.03 percent, the Palm Treo's Blazer browser is at 0.02 percent, and the multiple-device Opera Mini grabs 0.04 percent.

The key to the iPhone's success is the fact that it provides a unified, full browser experience, said Neil MacDonald, a Gartner analyst. By comparison, Windows Mobile is a fractured platform, with separate PDA and smartphone versions, as well as a version of the browser that doesn't support full HTML.

Windows Mobile tries to do too much with the devices it supports, such as running mini versions of Office, resulting in an OS that pleases no one, MacDonald said. Apple came into the market late, with its own hardware capable of providing the platform on which to run both regular and rich Internet applications. MacDonald recommended Microsoft do the same, using Silverlight as its rich-Internet app and a desktop-capable version of Internet Explorer for "regular" Internet apps. Such a move would require Microsoft to get into the hardware game so that it can create a unified user experience like the iPhone's, he noted. While Microsoft has avoided that approach in the past, its recent Zune efforts in the MP3 player space demonstrate it may be ready to reconsider that hardware/software separation.