Generally, it takes people a while to upgrade. For what it’s worth, I've heard from users who have Office 2007, but they're not using it. While the ribbons wow users who are new to Office, they just confuse old users. In addition, I know only one independent developer who’s had a request to upgrade a custom application to Office 2007.
Last week, Microsoft published a new Office 2007 compatibility tool, Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats as a free download. It allows you to open Office 2007 documents in earlier versions of Office.
What I find noteworthy is that it’s currently the second most popular download. That's just suspicious. Office 2007 lets you save a document to a version-specific format. In fact, you can even set the 97-2003 version save as the default. With that in mind, why would users need this download if they have Office 2007? Surely that rating doesn't represent the number of people who haven't upgraded but are receiving 2007 files. That just isn't believable.
Thanks to Jon Tydda of London England for the answer. According to an article by Dan Goodin in The Register, this download contains security upgrades for Office 2003.
I’m not sure why Microsoft has disguised an important security solution for Office 2003 as a compatibility tool for Office 2007. The security fix is part of Office 2007. If you've got Office 2007, you don't need this download. But, you don’t need Office 2007 to take advantage of the 2003 security fixes. Microsoft might consider identifying this download differently.