WWW2003 -- day two Facts and figures about WWW2003; W3C standards update; progress report on 802.11b-enabled community coverage.
A Web service is a software system identified by a URI, whose public interfaces and bindings are defined and described using XML. Its definition can be discovered by other software systems. These systems may then interact with the Web service in a manner prescribed by its definition, using XML based messages conveyed by Internet protocols.
Hugo Haas, W3C
As result of the above Web Services enable browserless consumption of services available at a URI. Good examples being the ability to purchase a book, CD, or any other item from Amazon without browser based interaction with the Amazon site (URI: http://soap.amazon.com/schemas2/AmazonWebServices.wsdl and UDDI Discovery URI: http://uddi.microsoft.com/discovery?businesskey=bfb9dc23-adec-4f73-bd5f-5545abaeaa1b) .
Further reading:
W3C Web Services Architecture Draft: http://www.w3.org/TR/ws-arch/
W3C Web Services Glossary: http://www.w3.org/TR/ws-gloss/