That's what WDDX stands for. It was created in 1998 by the folks at Allaire (headed by Simeon Simeonov) 7 years later the web is just starting to embrace the concept. Granted, not many folks are using WDDX, rather they are using SOAP, or REST web services.

Check out this article Jeremy Allaire wrote in 1998 called The Emerging Distributed Web. Allaire says:

...Fewer people, however, understand the implications of the infrastructure and platforms that are unfolding at an equally unparalleled pace. Organizations worldwide are rushing to deploy content and services on the Web. These mostly one-off applications are deployed on Intranets for worker collaboration, or business system automation, on Extranets and the Internet as frameworks to serve partners and customers. What companies don't realize in their efforts is that for every Web server they deploy, and every database or application connected to this Web, they are increasing the overall value of the global network.

It took about 7 years, and people are just starting to get this...