A Door to Automated Web Applications

In Japanese culture, your meishi conveys your place in the company, even in society, as well as your name, phone number, and email address. That is to say, in Japan, business cards matter. They convey complex metadata about the people who carry them. Like people, Web pages come in an abundance of shapes and sizes (and sounds). What makes them machine interpretable—and therefore a new medium for communicating information globally—is Hypertext Markup Language. HTML allows the structural markup of Web documents, distinguishing the elements of a page with tags and declaring the physical relationships among the various document elements (for example, “this is a new paragraph” or “this is emphasized from its surrounding text”). This organizes the display of information and allows humans to read and use it. To give machines this capability, however, requires semantic markup, identifying what each particular element means on its own (for example, “this is a home street address” or “this is an e-mail address”). Semantic markup would change what is now simply displayed content to machine-readable, structured content. The eXtensible Markup Language (XML) specification, first released as two working drafts in Spring 1997 by the World Wide Web Consortium (see the sidebar, XML Timeline), makes it dramatically easier to develop and deploy domainand mission-specific Web pages. In this article, we describe the evolution of the Web’s data representation from display formats to structural markup to semantic markup.