Comments are fantastic and make revisions much easier when working with clients. If you have not discovered how to insert comments in PowerPoint 2007 (it is not on the Insert tab) go to the REVIEW tab and the COMMENTS section.
Here is my sample slide with a comment added.
Open the Property Inspector (OFFICE BUTTON >> PREPARE >> INSPECT DOCUMENT) and the first item is COMMENTS AND ANNOTATIONS.
The report shows comments have been found in the presentation and gives the option to remove them.
Now when you view the slide, the comment is gone and the presentation ready, and safe, to distribute.
– Troy @ TLC