Every now and then, an idea comes along that in retrospect seems just so simple and obvious that everyone wonders why it hadn't been seen all along. Often when that happens, it turns out that the idea isn't really all that new after all. The Java revolution began by drawing on ideas from all the programming languages that came before it. XMLthe Extensible Markup Languagedoes for content what Java did for programming: providing a portable language for describing data.
XML is a simple, common format for representing structured information as text. The concept of XML follows the success of HTML as a universal document presentation format and generalizes it to handle any kind of data. In the process, XML has not only recast HTML but is transforming the way that businesses think about their information. In the context of a world driven more and more by documents and data exchange, XML's time has come.