XML lies at the core of Web services, and provides a common language for describing Remote Procedure Calls, Web services, and Web service directories.rnPrior to XML, one could share data among different applications, but XML makes this so much easier to do. In the same vein, one can share services and code without Web services, but XML makes it easier to do these as well.
rnBy standardizing on XML, different applications can more easily talk to one another, and this makes software a whole lot more interesting.