Cell phones have become consumers’ most personal technological devices. Some industry executives, along with consumer groups and security experts, are concerned that unwanted text messages on phones will be an even greater headache than unwanted computer messages.

Cell phone spam is particularly annoying to its recipients because it is more invasive -- announcing itself with a beep -- and can be costly.

Taber Lightfoot, an assistant director for new media at the Yale School of Management, is among those who have paid for the privilege of receiving cell phone spam.

"I was at work and I got so annoyed," she said of the first burst of three messages she received. She got another burst two days later.

"That is when I called Verizon and demanded they reimburse me $ 1.60 for eight text messages," Lightfoot said. "It wasn’t a lot of money, but it was my money."

American consumers are expected to receive an estimated 1.5 billion unsolicited text messages in 2008, according to Ferris Research, based in San Francisco, which tracks mobile messaging trends. That is nearly double what they received in 2006.

Of course that is a small percentage of the overall number of messages: An industry survey showed that consumers in the United States sent and received about 48 billion text messages in December alone. But for many people who are charged as much as 20 cents for an incoming message or are interrupted in the middle of dinner, even one is too many.

"The reason this really burns people up is because they have to pay for messages they don’t want, and they shouldn’t have to," said Chris Murray, senior counsel for Consumers Union, a nonprofit group.

Now some consumers, like Lightfoot, are monitoring their cell phones more aggressively for unwanted messages and, in some cases, demanding refunds. Computer security companies have developed products to help fight mobile spam. And AT&T, Verizon and others are making it easier for customers to block unsolicited messages and keep spammers at bay.

The fees that customers pay to receive messages are a source of profit for the phone companies. It is hard to estimate how much they make. Many consumers pay for a monthly plan that allows them to send and receive large numbers of messages. But for those without a plan, getting as few as 10 unsolicited text messages a month at 20 cents each would cost an extra $ 24 a year.

Communications companies say they are not interested in spam as a profit center. They want to one day exploit the power of customized advertising on mobile phones, and tawdry spam pitches threaten to make their customers hostile toward all commercial messages. The companies are trying to head off the problem before consumers revolt. (New York Times News Service)