Advertising Sent To Cellphones Opens New Front In War on Spam

Spammers use similar techniques to target people through text messages as they do through e-mail. They harvest phone numbers from databases or hack into the records of legitimate companies that have permission to send text messages, such as travel sites or online retailers. The guesswork involved in targeting cellphone numbers is easier than randomly selecting e-mail addresses; while an e-mail address has a unique sequence of characters and a variable length, phone numbers are 10 digits. Therefore, it is easier to blitz thousands of potential customers at once.

Most text messages are sent without any form of encryption, allowing tech-savvy spammers to intercept the messages and get access to personal information, said Larry Ponemon, founder of the Ponemon Institute, a privacy and security research firm.

As of 2005, federal agencies banned companies from sending unsolicited commercial e-mail and text messages to mobile phones. To receive promotional material or updates, consumers typically must text a message to a short code to opt in to the service.

But Simeon Coney, marketing director at anti-spam software maker AdaptiveMobile, said spammers are breaking the law, bombarding cellphone users with unwanted mail that could infect phones and BlackBerrys with viruses.

Consumer complaints about text-message spam have been sporadic, according to the Federal Trade Commission, the FBI and Consumers Union. But Coney said his firm is starting to see "overall increases in mobile-spam traffic."

Last year, Verizon Wireless sued telemarketers it said inundated its networks with more than 12 million unsolicited commercial text messages. In its lawsuit, the wireless carrier said it was able to block all but 4,618. Customers were hit with unwanted charges and the spam slowed legitimate traffic, according to Verizon Wireless.

Individuals have also taken legal action against unwanted messages they perceive as spam. In October, Lindsey Abrams of Illinois filed a complaint against Facebook for sending "unauthorized text messages" to her wireless phone number, which had previously been assigned to another Facebook member. "These messages can come during all times of the day or night and, because the senders are often hard to identify, can be seen as intimidating or unsettling," Abrams said in the complaint.

In 2006, Lei Shen, also of Illinois, sued District-based mobile marketing company Distributive Networks for sending her unauthorized ads in the form of text messages.

Nearly a quarter of U.S. mobile subscribers say they've viewed a mobile advertisement in the last month, and more than half of them responded to it by sending a text message, clicking on it or calling a specific number, according to a report released last week by Nielsen Mobile.

A separate survey conducted by M:Metrics, a Seattle firm that tracks mobile trends, found that 28 percent of the people who get text-message ads did not give permission to receive them, up from 19.5 percent eight months ago.

The rise of spam could spoil trust in text messaging as a mode of communication, not to mention its potential for mobile advertising, according to Charles R. Taylor, a Villanova University marketing professor who has studied online and mobile ads. "Trust is crucial for an ad to be effective, and the minute you start clogging up cellphones and BlackBerrys, it's a real turn-off and an invasion of your personal space."

The revenue generated by data services, such as text messages, has grown along with the consumer demand. About 20 percent of wireless carriers' total revenue now comes from the delivery of text messages, said Roger Entner, senior vice president for the communications sector for IAG Research. Each text message typically costs between 10 and 20 cents, although the four largest U.S. carriers -- AT&T, Verizon Wireless, Sprint Nextel and T-Mobile -- are rolling out flat-rate plans for text messaging. The carriers said they have rigorous filters to block spam, and they allow customers to block messages from certain numbers. They also try to remove charges for unsolicited spam.

"We have every incentive to stop spam texts from getting through, since we end up footing the bill for a lot of it," said Verizon Wireless spokesman Jeffrey Nelson. "The longer a service like text is out there, the bigger the bulls'-eye gets."

Staff researcher Richard Drezen contributed to this report.