Tesco.com is a UK e-commerce success story. Although a helping hand from a parent company with a £14bn turnover last year undoubtedly helped it weather some of the early turbulence that has drowned other fledgling dot-coms, Tesco.com's smart attitude to technology has also been a major differentiator. Testament to this is that US grocery chain Safeway has licensed its whole Web front end. Instead of getting buried in overheads building expensive warehouses like the competition did, Tesco focused on a cost efficient programme to base its Web strategy around existing logistics and pick products directly from its network of 720 UK stores. And it is this cost efficient approach that has seen the company explore the write-once, use-on-multiple-platforms benefit of Web services. Allying itself closely with Microsoft's .Net platform, Tesco.com has overhauled the entire structure of its site to take advantage of emerging access devices such as PDAs. "Tesco.com found itself in a position where it was producing multiple and essentially redundant pieces of code to facilitate multiple platforms. Our reuse was really poor; we implemented many solutions to the same problem," says Jon Higgins, Tesco.com head of e-commerce development. "What we decided a while ago was that we wanted a model that would support multiple clients, affiliates and our own Web site, which all had requirements for the same kind of data," he adds. "We could implement the Web service once and then the Web service would be ultimately reusable by any of those clients and indeed anything that happened in the future." Tesco.com took around a dozen business objects, such as customer log-in, check-out, "show me" promotion and exposed them as Web services and configured their clients to use them. Higgins claims that maintenance overheads are much lower as a result and the consistency of information is better; it eliminates the possibility that you are giving different information to different clients because they are all using the same service. Code written as a Web service is also being used for another unique platform. Conscious of the need to keep connection costs down for a customer base mostly surfing via dial-up, Tesco.com has developed an offline client that allows users to update their shopping lists offline. The importance of this offline client to Tesco.com could be seen as one of the main reasons that it has decided to go with a complete Microsoft approach to Web services. Opting to use the Web technology of a company that practically owns the desktop must help when it comes to getting Tesco.com's offline client, and Web site in general, to perform efficiently in the Windows environment used by the vast majority of its customers.