•XML documents are used to transfer data from one place to another often over the Internet.
•XML subsets are designed for particular
applications.
•One is RSS (Rich Site Summary or Really Simple Syndication ). It
is used to send breaking news bulletins from one web site to another.
•A number of fields have their own subsets. These include chemistry, mathematics, and books publishing.
•Most of these subsets are registered with the W3Consortium and are available for anyone’s use.