Update as of 10/26/2010: YES!!!

If you're using the old version of Mac Office (2004), the answer is yes, and you can download the FREE version of Annotate to try it out. If you just got Mac Office 2011, then you're golden. If you're using Mac Office 2008 you are out of luck.

Mac Office 2008 doesn't support any of the technologies we use to extend Word.

The current version of Annotate (both FREE and PRO versions) is slightly different than our Windows versions. The same library of 70+ built-in comments are there, but you can't edit them dynamically. This is why the Mac Office version is $25 rather than $45.