Vivotechs approach allows the retailer to deliver the incentive both instantly and before payment, so the customer has the chance to use the incentive right away. "The intent is to impact your [customers] behavior before they get to the checkout line," he said. A consumer would walk into a store and point his or her PDA to a kiosk. The palmtop would quickly identify the consumer and flash an alert that, for example, the customers favorite shoe vendor is having a 40 percent off sale for select customers and that the consumers particular shoe size and favorite color are in stock.Are retail IT execs too hesitant to make changes? Click here to read our columnists opinion.The next stage of the software will allow true, ongoing, two-way communication. When that happens, the customer will be able to message back, "Can you set aside one pair in black and one in red for me? Ill pick them up in two hours," or "Make that offer 50 percent, and Ill buy four pairs right now." The cell phone or PDA would facilitate a real-time messaging conversation. Vivotech is working with Symbianwhich makes an operating system for data-enabled cell phonesand Verifone, a POS vendor, among others, company officials said. Jupiters Cundiff applauded the idea behind Vivotechs efforts but questioned how successful it will be and, if it is successful, how quickly it will happen. "There is no doubt that the coolness factor is here," he said. "But this is going to be a little more difficult than Vivotech would have you believe." From the perspective of how many devices are ready to handle such an application, its clear that PDAs are way ahead of cell phones. But Cundiff said he sees this being practical only with a cell phone because consumersespecially at night and on weekends, when a lot of purchases happendo not carry around PDAs nearly as often as they carry their cell phones. Most cell phones today do not support such capabilities, so for Vivotechs strategy to work, a lot of consumers are going to have to upgrade, he said. Consumers wont likely upgrade just for the privilege of making purchases easier and seeing ads, so the onus falls on the cell phone companies to get consumers to upgrade. The telcos "have been salivating [about making purchases through cell phones] for years," he said. "But its going to be tough to get consumers to buy those next-generation phones." Editors Note: This story was updated to include comments from Jupiter Research analyst Bruce Cundiff. Check out eWEEK.coms Retail Center for the latest news, views and analysis of this vital industry.