I thought Doug made some good points in his article, but there was still come skepticism at times. I guess I didn't make it clear, but we do completely conform to the W3C XML 1.0 standard, so any parser that supports that should be able to work with our files. If anyone has found that our XML files don't work with a particular parser, please let me know.
Kurt Cagel's comments are worth drilling into a bit more. It's true that we've been evolving our XML support in Office for a long time now (since Office 2000 as he mentions). The big shift this time is that we are now saying that the formats will be full fidelity and the default for Word, Excel, and PowerPoint. That's a huge step forward. The comments on the complexity of the XML output really has to do with the feature set in the applications more than anything else. Word, PPT, and Excel have a ton of functionality. We have to support all that in XML. We can't have the conversion from the old binary formats into the new XML formats result in any kind of feature loss. It needs to be 100% full fidelity. That means the schemas themselves will be pretty large. That doesn't mean all files have to be extremely complex though. If you don't care about most of the functionality and just want to create a simple file, you can do that. I posted last month an example of doing just that: Intro to Word XML Part 1- Simple Word Document