Article on Web Services

I just got an issue of Oracle Magazine that has an article by John edwards
on web services
(http://www.oracle.com/oramag/oracle/02-mar/index.html?o22web.html
<http://www.oracle.com/oramag/oracle/02-mar/index.html?o22web.html> ).  This
article defines web services as "self-contained, self-describing, modular
applications that can be published, located, and invoked via the internet".
They go on to make a distinction between "simple web services", which
provide a basic request/response function via SOAP, UDDI and WSDL -- and
"complex web services" that involve "multiparty, long-running transactions,
perhaps involving several trading partners ...".  Although they do not use
the term "architecture", I believe that they define the following
architectural components for a web service:
*	It is able to expose and describe itself to other applications,
allowing those applications to understand what the service does. 
*	It can be located by other applications via an online directory, if
the service has been registered in the directory. 
*	It can be invoked by the originating application by using standard
protocols. 
I'm passing this along as "useful input", reasonably stated, not as golden
words or anything.