What role does XML play in modern nTier architectures?

Question

I have seen a lot of job postings for ASP.NET and server engineer positions, and they always seem to list XML and XSLT as one of the skills that is valuable to them. I am wondering what role XML plays in modern systems. How are people using XSLT with XML in nTier systems?

Answer 1

Andrew has very succinctly stated the primary roles of XML based data in .NET systems - Providing a templated method for configuration of applications and interoperable transfer of data between disparate platforms.

XSLT being the primary mode of transformation for XML data into XML/XHTML is extensively used because of the same reasons. An XML often needs to be converted to another XML with different structure, or one may want to render an XML datasource directly as HTML output. XSLT is almost indispensable in such cases, even though the transformation could be done manually by writing a lot of DOM traversal code.

Using similar logic, XPath is also used because it provides the most basic and powerful way of traversing the XML hierarchy to query data based on its location in the XML.