An O'Reilly weblog entry talks about the great benefits of web services for application integration. I'm a bit more sceptical.

While WebServices certainly make the technical part of integration easier I'd question whether that was ever the major difficulty. In my experience it's always far harder, and involves more difficult to obtain resources, to understand the meaning of the data being exchanged than it is to actually exchange it.

Standard schemas etc. for the web services xml will help but will still require each participant to understand the standard schema and map their own internal data to the it. In fact, this now introduces two mappings with the possiblity for error and misunderstanding where there would previously only be one.

It seems that developers always like to try to solve the "easy" technical problems, i.e. how to map an object into xml, rather than attempt the more difficult and fuzzy semantic ones, i.e. how do I know that we both agree on what "production lead time" really means. We can reinvent CORBA, or EDI, as web services, but, while doing so will help keep us all employed, if we don't tackle the semantics there won't be any substantive change.