Now that you've seen how developers can use XML to create documents with self-describing data, let's look at how people are using those documents to improve the Web. Here are a few key areas:

• XML simplifies data interchange. Because different organizations (or even different parts of the same organization) rarely standardize on a single set of tools, it can take a significant amount of work for applications to communicate. Using XML, each group creates a single utility that transforms their internal data formats into XML and vice versa. Best of all, there's a good chance that their software vendors already provide tools to transform their database records (or LDAP directories, or purchase orders, and so forth) to and from XML.
• XML enables smart code. Because XML documents can be structured to identify every important piece of information (as well as the relationships between the pieces), it's possible to write code that can process those XML documents without human intervention. The fact that software vendors have spent massive amounts of time and money building XML development tools means writing that code is a relatively simple process.
• XML enables smart searches. Although search engines have improved steadily over the years, it's still quite common to get erroneous results from a search. If you're searching HTML pages for someone named "Chip," you might also find pages on chocolate chips, computer chips, wood chips, and lots of other useless matches. Searching XML documents for <first-name> elements that contained the text Chip would give you a much better set of results.

I'll also discuss real-world uses of XML in Case studies.