XML promotes easy data exchange and because XML documents are text-based documents, they can be easily created, manipulated, stored, and transmitted.
There is no need to worry about any proprietary data formats, one of the problems that hindered the easy exchange of data
between applications. XML documents can also be easily distributed and displayed on the Web.
XML uses beyond the Web
XML documents contain data inside custom tags that describe the data. Once an XML document is created, it may be shared to take advantage of the data content or rendered by multiple devices.
The same XML document may be viewed on browser, a Personal Digital Assistant (PDA), or a cell phone. In each case, the XML document will transformed so that it can be viewed in
the respective device. For example, there are software programs that will transform an XML document into an HTML document so that the later may be rendered by a browser. This creates an environment where pervasive computing becomes a real possibility: the same XML document is transformed and viewed by many different devices.
XML as a metalanguage
With XML, one can create customized markup languages that are also extensible.
Many such languages are appearing in vertical business domains. Here are some examples: