How it works

Like Hypertext Markup Language, Extensible Markup Language is tag-based. To use XML, users simply insert tags as they write the code. While HTML indicates how to format content on a Web page, XML, which is a standard defined by the World Wide Web Consortium, reports what is in the content and how it is organized.

"An XML standard will specify, for example, that there will be a tag called "address' and it will have this kind of data in it: street, city and state," explained Alan Brown, chief technology officer of Learnframe Inc., an electronic-learning vendor. "So you have a street embedded in an address, not an address embedded in a street. XML specifies the hierarchical structure of data."

A big benefit of XML is that it is used across computer platforms and industries. "It's being used heavily in the financial industry for financial statements," said David Alexander, a research analyst at Frost & Sullivan, San Jose, Calif. "XML tags make it easier to look at the same information across different applications."

That widespread use also means it is often easier to find developers who are familiar with it. "Any technology that has broad acceptance across many markets is advantageous," said Lori Gavin, Learnframe's director of software development. "Wide acceptance means most developers will know how to work with it."