What XML Is Not

XML is not a programming language.  It is only a markup language.  XML contains no control structures or variables.

XML does not specify how its data is to be displayed.  Unlike other markup languages such as HTML and DHTML which only define how data is to be displayed, XML only defines the structure and semantics of data.  It is up to user how to process and display the data within an XML document.  There are, however, XML tag structures that define how other XML data is to be displayed, including XSLT, XSL FO, SVG and SMIL.

XML is not a database.  However, a database may contain XML data.

Unlike its parent (SGML), XML is not a proprietary markup language.  The standard is maintained by the World Wide Web Consortium and is free for public use.