Office 2007 uses a new (and improved?) format (they added an x to all their file name extensions, read more about them here).  This could be all good and well if it had not been for the fact that new versions of Office now uses these formats per default.  Okay, a user a bit savvy might sooner or later notice the "x" at the end of all filenames... but only the users that have disabled the setting in Windows to hide these formats...

This leaves us with senders, running Office 2007, unable to tell if they saved the file in docx or doc format, and the recipients with Office 2003, unable to read these files.  Even though there is an update, a lot of users aren't comfortable with doing that... heck, I'm scared of doing unneccessary stuff to my wobbly M$ installation!

The end result becomes pretty predictable: chaos, disillusioned users, and ... a great day to start talking about OpenOffice.org? (even though it does not yet support the Office 2007 format).