Since the recent announcement that the next version of Microsoft Office would move to open XML formats as the default file format in the next version, I've seen some questions raised about why the XML formats which were standardized with OASIS weren't used. This point is addressed in a comment by Jean Paoli in the article Microsoft to 'Open' Office File Formats which is excerpted below

"We have legacy here," Jean Paoli, Senior Microsoft XML Architect, told BetaNews. "It is our responsibility to our users to provide a full fidelity format. We didn't see any alternative; believe me we thought about it. Without backward compatibility we would have other problems."

"Yes this is proprietary and not defined by a standards body, but it can be used by and interoperable with others. They don't need Microsoft software to read and write. It is not an open standard but an open format," Paoli explained.

When asked why Microsoft did not use the OASIS (Organization for the Advancement of Structured Information Standards) XML file format, Paoli answered, "Sun standardized their own. We could have used a format from others and shoehorned in functionality, but our design needs to be different because we have 400 million legacy users. Moving 400 million users to XML is a complex problem."

There is also somewhat of a double standard at play here. The fact that we are Microsoft means that we will get beaten up by detractors no matter what we do. When Sun announced Java 1.5 5.0 with a feature set that looked a lot like those in C#, I don't remember anyone asking why they continued to invest in their proprietary programming language and platform instead of just using C# and the CLI which have been standardized by both ECMA and the ISO. If Microsoft had modified the XML file format so that it was 100% backwards compatible with the previous versions of Microsoft Office it is likely that same people would be yelling "embrace and extend". I'm glad the Office guys went the route they chose instead. Use the right tool for the job instead of trying to turn a screwdriver into a hammer.

It's a really powerful thing that the most popular Office productivity suite on the planet is wholeheartedly embracing open formats and XML. It's unfortunate that some want to mar this announcement with partisan slings and arrows instead of recognizing the goodness that will come from ending the era of closed binary document formats on the desktop.