The CrackBerry's sticky and addictive nature, its ease of integration on the back end and its robust security features contribute to its meteoric rise (9 million users and counting). "Businesspeople see it as a requirement just as they do a desk phone," boasts Mike Lazaridis, president and co-CEO of Research In Motion, BlackBerry's maker. But not everyone saw the BlackBerry's potential in the early days.

"I was the first in my firm to have a BlackBerry," says Steven Sommer, CIO and CTO of law firm Hughes Hubbard & Reed, which has 330 lawyers worldwide. "I tried to give one to my boss, and he said, 'Get out of here. I want to carry around my 20-pound laptop.'"

A 2007 Economist Intelligence survey of 532 global executives (more than 80 percent from outside the United States) found that the top mobile device inside their companies was a conventional mobile phone (62 percent). Lagging in second place was a Wi-Fi-enabled laptop at 44 percent. The survey suggests that the mobile phone is king and the way in which international business "gets done."

In the United States, however, the laptop is still considered essential. "I would like nothing better than to not have to carry my laptop [on business trips]," says Steven McIntosh, senior vice president and CIO at Jackson Enterprises, which has 20 wineries worldwide. Like many businesspeople, he uses his PDA whenever possible, but connectivity issues mean he carries his laptop as a backup.

The laptop flourished in the United States in part because it cost less here than in other parts of the world. Ten years ago, laptop prices in Europe were double the U.S. price. Mobile phones emerged as a way of life in Europe and Asia because they were much cheaper and demand for service pushed those countries—which were less geographically dispersed than the United States and easier to blanket with wireless signals—to invest heavily in their mobile networks.

In addition, since Asians typically spend one to three hours per day commuting to and from work on a bus or train, a big laptop is impractical, says Brian Bonner, CIO of Texas Instruments, which has operations in Asia and Europe. Bonner points out that devices such as Nokia's N95 offer Asian users e-mail and music services, DVD-like video, a 5 megapixel camera and support for Web browsing and GPS mapping, "all in one device."

But Stateside, by not provisioning their workers with integrated mobile devices—and by not managing or standardizing them—business has created a culture of mobility in multiples: Overburdened knowledge workers may carry a laptop, cell phone, PDA, MP3 player and digital camera at the same time. Which raises the question: How untethered are you if, on a business trip, you have to lug a laptop, have your BlackBerry in hand, a mobile phone attached to your belt and whatever other device you might need?