Marketers at the Cambridge Side Galleria Mall had tried it all -- mass mailings, print ads, radio spots. But such tactics were no longer bringing in the shoppers, and the Cambridge, Mass., mall was on the hunt for something truly attention-grabbing. So last winter, Issie Shait, vice president of operations at the 116-store shopping center, turned to a new marketing medium: the screen of the cell phone.

Shait's team collected the phone numbers of nearly 2,000 shoppers. Over a six-month period, the customers received, via text message, 39 discount offers from 19 tenants -- messages like "Twenty percent off at the register" or "Free appetizer when you dine with a friend." Shoppers simply presented their phones at the mall's information desk in exchange for paper coupons to redeem in stores. According to Shait, an astonishing 80% of all the text-screen coupons were converted. "The tenants that participated all saw a jump in their sales," he says.

Welcome to the next frontier in direct marketing -- the mobile phone. At a time when consumers hang up on telemarketers, delete spam, and toss direct mail into the trash, they remain surprisingly receptive to marketers "texting" them. Text message, or short-message service (SMS), campaigns allow companies to zap incentives -- like coupon codes, raffle numbers, or VIP passes -- straight into the hands of customers. And though such campaigns have been used for several years by megabrands like Pepsi and MasterCard in Europe and Asia, they're still new here.

Popular television programs, like American Idol, use SMS technology to poll viewers. And marketers are sure to follow suit. Some 65% of American adults own cell phones, says Yankelovich Research. And 78% of all U.S cell phones, or 112 million devices, are text-message enabled, according to the Mobile Marketing Association.

Access to such a huge number of consumers is tempting. But experts warn marketers not to "text" people without first obtaining permission. "Blasting alerts to a list of numbers is too reminiscent of spam," says Alex Campbell, co-founder of Vibes Media, a mobile marketing agency in Chicago. "Instead, use traditional media like direct mail or outdoor ads to get them to text you first."

In text-based marketing, brevity is everything. Messages can contain no more than 160 characters, including spaces, and no pictures. At least for now, it's hard to mount a campaign without the help of an agency. That's because to do it right, it helps to have a prior relationship with cell-phone service carriers -- which possess a limited supply of lines from which to send messages and receive replies. A campaign can cost anywhere from $5,000 to more than $100,000, though carriers often look to sponsor text promotions.

Pure Promote Group in Chicago has run text campaigns sponsored by Verizon. The company finds the high-tech image associated with texting plays perfectly with the 21- to 34-year-olds it is eager to attract to its nightclub parties. Last summer, fans who bought tickets to see acclaimed DJs Deep Dish were able to receive confirmations by text. Some 250 clubgoers who opted in showed their phones to bouncers and were escorted to the shorter line for VIPs. The text tickets helped the club reach its capacity, and Pure is planning more such campaigns. "You can forward information from your phone to your friends," says Pure vice president of marketing Jay Prasad. "And it won't get lost like a flyer, or stuck in your computer."