With this add-in you can permanently remove hidden and collaboration data, such as change tracking and comments, from Word 2003/XP, Excel 2003/XP, and PowerPoint 2003/XP files.
When you distribute an Office document electronically, the document might contain information that you do not want to share publicly, such as information you’ve designated as hidden or information that allows you to collaborate on writing and editing the document with others.
Download: Office 2003/XP Add-in: Remove Hidden Data
[Via Bink.nu]
I have seen some discussion on people being unaware of the ‘hidden data’ in their Office files. This add-in may be helpful.