Uche Ogbuji
Fourthought, Inc.

One of the most important requirements for highly-automated Web Services
is a rich description mechanism.  In order to narrow down the
negotiation and discovery of services that fit a particular contractual
and technical profile, this information needs to be made available in an
accessible way for machine processing.  There have been several
initiatives to develop systems for encoding and querying such Web
service descriptions, among them the Web Services Description Language
(WSDL) and Universal Description, Discovery and Integration (UDDI).

WSDL uses a specialized XML format for service descriptions, specifying
key metadata in a formal structure.  This serves two purposes.  One is
to define a vocabulary for the service descriptions and one is to define
the abstract and serialized form of these descriptions.  The second
purpose, however, is already well covered by the Resource Description
Framework (RDF), and a system that uses the vocabulary developed in
WSDL, and builds on top of the RDF model and syntax would offer a great
deal of advantages.  Such a system is described in the paper
"Supercharging WSDL with RDF" (see
http://www-106.ibm.com/developerworks/library/ws-rdf/index.html?dwzone=ws). 
This approach would allow normalized integration with other
vocabularies, and would allow WSDL systems to take advantage of the
large body of work that is being done on RDF.

In addition, UDDI, which is a comprehensive API for querying various
aspects of Web services, could gain similar benefits if these aspects
were encoded in an RDF vocabulary and the query language itself merely
one of the many current approaches to querying RDF data.