Netbook computers, which Gartner refers to as "mini notebooks," have already changed quite a bit in the year since they were first introduced. When netbooks hit the market last year with Asus's release of the Eee PC, they typically had 7- to 8-inch screens. Despite the $300 price tag, consumers found the screens too small. And most shipped with the Linux, an operating system considered daunting by most consumers.

With this year's release of netbooks with 9- to 10-inch screens and widespread availability of models running Windows XP, demand has taken off. The pint-sized portable computers dominate the top five slots on Amazon.com's list of best-selling laptops, sporting prices of less than $400. In the three months ending September, sales of netbooks grew 160 percent, reaching 5.6 million, according to market tracker DisplaySearch. During the same quarter, Apple only sold 4.7 million iPhones.

But that does not mean that netbooks are ready to take over the enterprise, says Leslie Fiering, research vice president for mobile computing at Gartner. "They are coming in as companion notebooks, as second notebooks, that workers are buying themselves," she says. "The question is whether they are ready to come in as a sanctioned corporate laptop—no."

HP's sub-$400 Netbook is typical of the new less-than-five-pounds crowd

While the price is persuasive, the machines are not yet mature enough for the workplace, Fiering says. Most companies need Windows XP Professional or Windows Vista, not the Windows XP Home edition or Linux OS loaded on netbooks. At a typical 1024-by-600 pixels, the notebook screen resolution is still too low for many applications; surfing the Web, for example, frequently requires users to scroll their browsers side-to-side to view an entire page. And the netbook's single-core processors—the most common one being Intel's Atom—are not powerful enough to run many applications without noticeable delays.

"If you are a CIO who is trying to plan for the future, it is hard to commit to a platform like that," said Roger Kay, president of technology-market researcher Endpoint Technologies Associates. "Most workers want a fully featured notebook, even if it is just for watching movies on the plane."