This isn't want Joel is talking about here. On the backend, all .docx files use XML. Joel is saying the root XML format was difficult to work with. What my ar

This isn't want Joel is talking about here. On the backend, all .docx files use XML. Joel is saying the root XML format was difficult to work with. What my article is about is this: Microsoft used to allow users to write their own custom XML rules on top of Word. (This was mostly app developers using XML for macros rather than end users, and overall it was very rare.) This is the feature that was at issue with the patent. Sorry if this was not clear!