Not just XML, but there is a whole world of interoperability opening up with Web Services, and XML (SOAP) is becoming quite popular. As a DB developer in a web dev group I've had first had experience with the power that comes with web services.  This is definitely THE "killer app" for XML.

Like it or not, XML is here to stay, and if you don't use (for religious reason's or other) you're going to miss out on a lot.

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