Although it's too bad that Microsoft didn't use the OASIS standard for XML schema, they claim it's solely because of their intent to remain backwardly compatible with MSO's prior binary formats. It was suggested that in a future version they would eventually go that route, though. A video
interview with Brian Jones of the Microsoft Office team demonstrates some really cool things, and their press release is
here and here is Brian's
new blog. What's cool is that you can see
everything in an office document now, and since it's zipped, you can open the file and exchange parts such as macros, pictures, excel sheets, whatever, and when you reopen the file, voila! there it is, updated.
If you're an OpenOffice user, this is also good news because starting with MS Office 12's new formats, OpenOffice will be able to convert MS Office files with perfect accuracy, and ironically, this should spur further adoption of OpenOffice! If you're a long time MSO user like myself and have over a decade of files locked into various closed Microsoft binary formats, this extends the half-life of your document integrity almost infinitely.