Over the past few years, XML has emerged as the computer world’s favorite three-letter acronym. At first, XML was a curiosity about which a few technological boffins were getting a little over-excited—an interesting technology looking for a place to happen. Gradually, however, developers came to realize the enormous potential of a platform-neutral way to exchange structured data over the Internet, and we started to see people using XML in new and interesting ways. Of course, there’s nothing particularly noteworthy about this trend; in an industry where new technologies are often obsolete before they even get to market, it’s not unusual to see a mass adoption of the latest and greatest technological fashion. But XML has proved to have more staying power than many of the other techniques and technologies that have risen and fallen in the computing world. One reason for XML’s support is that unlike many new ideas, it doesn’t require us to throw away all our old ones. In fact, XML makes it easier to retain your existing systems and integrate them with new ones. It also makes it possible to integrate your applications with those of your trading partners, even if they’re using platforms and systems completely different from yours.