Forgot that I Blogged this a while back, but what is cool is that I have just tried to open a docx in Word 2003 and it actually prompts me to download:
[Microsoft Offic Word]
This file was created by a newer version of Microsoft Word. Do you want to download a compatibility pack so that you can work with this file?
How does it know? An update must have been applied or it’s in the docx. Anyway it takes you to the download (http://www.microsoft.com/downloads/details.aspx?familyid=941B3470-3AE9-4AEE-8F43-C6BB74CD1466&displaylang=en) page to get the update … that is cool!