Clay Shirky has published an excellent article on what Web Services can and can’t do, and whether the twain shall meet.

As an analogy, take English and Danish. They have almost identical alphabets but are nevertheless different languages. An alphabet is a limited set of characters that can represent an unlimited number of words through recombination. XML is an alphabet, not a language. It provides the primitives for describing larger concepts, and it works by allowing an unlimited number of semantic concepts to be encoded using those primitives. Any XML parser should be able to declare any given XML document structurally valid — analogously to the way native speakers can tell if a word is or isn’t part of their native tongue — but that says nothing about whether the contents of that document will be comprehensible to the recipient.

At best, XML makes it possible for businesses or developer groups to share data, provided they agree on the semantics of that data in advance. This is not to say XML is not an enormous advance. It plainly is. However, its advance lies in aiding data interoperability where shared semantics can be assumed. It does nothing at all to create semantic interoperability.

Link Discuss (Thanks, Scott!)