Third Look

(You can view the text with images at http://www.chrisgreaves.com/Office2007User/)

I created a new document in Word2007 using one of my Under-The-Hood macros “TypeDateConst”. The macro ran (a good sign!) and I saved the document.
The document was saved with a DOCX extension.
Examining the file in Notepad I see the give-away initials of Phil Katz. PKWare.

Sure enough, I can view the file with PKZip version 2.6:

Word2007 documents are XML-based and are stored in compressed form.
Can I open a Word2007 document in Word2000?
Yes I can. I execute the docx file from within Windows Explorer, and since Word2000 is open, Word2000 receives it.
Office2007 must have placed cunning interceptors to obtain the document, and roll it back to the standard of the open word processor.
Now, this may work only as long as I have Office2007 installed.