I was curious about the i4i v. Microsoft patent infringement case, so I did a little more research into it. I’ve seen a lot of tech blogs and news sources that give a cursory examination and all seem to be parroting each other, so I thought I would give another point of view.
To clarify what some other reports have misstated, it’s not XML (eXtensible Markup Language) itself that’s at issue since it’s an open standard. It’s the use of Microsoft's "Custom XML" as a type of metacode for storing and manipulating documents and information about the documents and their data. Specifically, using a "metacode map" to distinguish the Custom XML from the content stream. This is a key distinction since many people have speculated cynical reasons for i4i targeting Microsoft and not every software vendor that uses XML or even going after the XML standard itself.