XML tags the selected elements of the content documents for their meanings
and makes it possible for computers to manipulate and interpret their data automatically and perform operations on the data without human intervention.
XML Provides a Standard Format for Data exchange, enabling Web services to pass data from one process to another.
Web Services communicate through XML messages over standard Web Protocols.
SOAP (Simple Object Access Protocol) is a set of rules for structuring messages that enables applications to pass data and instructions to one another.
WSDL (Web Services Description Language is a common Framework for describing the tasks performed by a Web Services and Commands and data it will accept so that it can be used by other Applications
UDDI (Universal Description, Discovery, and Integration enables a Web Service to be listed in a Directory of Web Services so that it can be easily located.