Unexpected Rush
"You can easily lose money on mobile broadband if you do it in the wrong way," said Bjorn Amundsen, director of mobile network coverage for Norway's Telenor.

"We have had to be careful not to invest too much -- because the only thing that would happen if we did would be to increase in data traffic without an increase in our profits," he said.

Few mobile firms expected the changes to user behaviour brought about by 3G cards.

For example, the technology allows a banker to follow the progress of his portfolio from his laptop in the back of a New York taxicab, or a photographer to upload pictures of a Paris soccer match instantly from the side of the field.

But even in areas where 3G technology has been rolled out, mobile networks weren't designed for such heavy traffic.

Base stations can only handle a certain amount of data, which must be shared by all users in a given area.

So if everyone on Wall Street uses their iPhone at lunchtime to watch video, the network can experience slower connections or service outages.

Michele Campriani, CEO of Accanto Systems, which markets software to track data traffic in telecom networks, says the company has signed 15 contracts with mobile operators in the past year to monitor problems due to traffic overload.

He says telecom executives see the data explosion as a serious threat: "They're all very concerned. If they don't manage this moment carefully, some mobile operators will run into major problems that threaten their very profitability and viability. Some may not survive."