I am standing in the Microsoft Booth at the <XML2006/> conference in Boston. With me are Craig Kitterman, Adam Wiener and Stan Kitsis. I have had a great time talking with customers from such exotic places as Denmark, China and New Jersey.
The hot topic at the XML Conference is OpenXML. OpenXML is the default file format for Office 2007. If you rename a Word 2007 file from .docx to .zip you will be able to open up the contents in WinZip:
The various components of the file are defined within the contained XML files. There are content specific files, meta information files and relationship files. Relationship files inform Word (or PowerPoint or Excel) how the file hangs together.
This feature of Office 2007 opens up the file format to any developer on any platform, allowing programmability on the client or on the server, in your language of choice. This is a tremendous step forward in opening up Office files for interoperability.