XML - Managing Data Exchange: "Introduction to XML"
XML is a SGML-based language related to HTML; however, XML is in some ways more flexible but in other ways demands more attention to detail. The differences between the languages have led to a sort of division of labor: HTML is used for delivering most core content on the Web, while XML is used for data-heavy applications that require customizable data structures. Even so, using the style sheet language XSLT, XML files can be converted into HTML files on the server before delivering those HTML files to the client or web browser over the Internet. This brief introduction will not teach you to code XML, but will hopefully help you identify cases in which XML is useful.