Smart-phone sales have already increased by 75.5 percent in the last year to 37.4 million units, and will grow by a further 66 percent during 2006, according to data released last week by the analyst firm.
Sales of PDAs also continue to rise, racking up a 5.7 percent increase in the last year to 7.4 million units. Growth of 6.3 percent is predicted for 2006, as PDAs continue to be eclipsed by more voice-centric smart phones.
The distinction between PDAs and smart phones is increasingly unclear, as both product types gain new features and converge on each other.
Gartner defines a smart phone as "a large-screen, voice-centric handheld device designed to offer complete phone functions while simultaneously functioning as a personal digital assistant." It defines a PDA as "a handheld computer that serves as an organizer and electronic notepad."
But these definitions are less clear than they may appear. Gartner reported that 53 percent of all PDAs shipped in the first half of 2006 featured integrated cellular capability, up from 46 percent during the same period in 2005.
"We classify them after looking at the primary purpose of the device, which is reflected in the design of the device," Roberta Cozza, a co-author of the report, said on Monday. "There are users that make their buying decisions after looking at the form factor."
Cozza conceded that "all categorizations are, at the end of the day, arbitrary," but insisted that Gartner's classifications reflected differing trends between types of devices. She noted that the Symbian operating system dominates in the smart-phone market, while Microsoft's mobile software has the lead in the PDA field.
"PDAs started as a consumer phenomenon, but are now being more chosen by enterprise users, and this is being driven by wireless e-mail. With regards to smart phones?we see that the market is currently still mostly driven by consumer purchases. What we would expect to see going forward, as Microsoft gets its act together, is more enterprise-grade smart phones in 2007."
The only market where sales of PDAs continue to outstrip those of smart phones is in North America, which represented 45 percent of the worldwide market for PDAs in the first half of 2006, according to Gartner.
The worldwide market leader across both device types continues to be, which accounted for 42 percent of PDA and smart-phone sales in the first half of 2006 and which represents half the global smart-phone market.
However, the fastest growing smart-phone vendor is . It saw shipments rocket by 103.5 percent in the first half of this year, thanks to sales ofin China. The report's authors note that Motorola's Microsoft and Symbian-based devices have had relatively lackluster success.
BlackBerry manufacturer Research In Motion continues to command the PDA market with 13.5 percent year-on-year growth, but Palm's share fell as the company shifted its focus to sales of its Treo smart phones, which accounted for 57 percent of Palm's mobile device shipments in the first half of 2006, according to principal Gartner analyst Todd Kort.
David Meyer of ZDNet UK reported from London.