XML: not a silver bullet, but a great pipe wrench

■ XML (Extensible Markup Language) provides both a standards-based way to identify the information that is of importance in a particular application, and the ability to process information tagged according to highly user-specific requirements with general-purpose software, such as editing tools, composition engines, and electronic browsers. The power of XML comes in part from principles that guide the design of good XML applications: separation of format and presentation information from document markup; consistent and clear text tagging; context-dependent processing; and hierarchical structures. But these alone do not explain the real power of XML, which lies in the ability to create tag sets and markup languages customized to the needs of the particular application. A custom XML tag set allows the user to identify all of the types of information that are needed for search and retrieval, formatting, and tracking. Any type of information your end users may want to find, or not find, can be identified, and expensive distinctions among types of information that are not important to you are not made. Note, however, these phrases from the preceding paragraph: “way to identify”; “ability to create”; and “can be identified.” XML provides a way to do these things, but does not do them. XML should be thought of as a useful tool, but not as a solution to any problem. here seems to be as much excitement about XML as there has been on any related technology since the Web went public. The hype surrounding XML has created such unreasonable expectations that there are already people trumpeting its failure, primarily because it hasn’t become instantly ubiquitous. XML is being hailed as the future of the Web, the replacement for HTML, the replacement for Java, and the technology that will create precise Web searching. XML will be easier to use than SGML, more powerful than HTML, and will enable secure electronic commerce. XML is the Internet’s Silver Bullet—such is the hype. XML will not leap tall buildings at a single bound, nor will it solve all of the problems of retrieval on the Web. XML will transform the Web in much the same way barbed wire transformed the American West. Barbed wire didn’t do anything. But using barbed wire, a lot of people did a lot of hard work and changed the culture from one of open ranges to one of farms and property rights. XML is an enabling technology; well designed XML can provide a valuable tool in the effort to provide more precise and more powerful searching on the Web. XML will replace HTML in those situations in which HTML is insufficient to meet a need. XML software is easier to build than SGML software and more appropriate for Web environments, but authoring documents in XML is unlikely to be any easier than authoring in SGML. The ease of authoring in both XML and SGML is dependent on how well the document structure meets the author’s needs and on how graceful the authoring application is. And interchange of information in XML depends on the development and promulgation of shared XML tag sets.