Comments

There are a couple of ways. One is to create a comment, then edit it and clear the Author field, and then use that comment's properties as the new defaults. You'll also need to go to Edit (or the Acrobat menu if you're on a Mac) - Preferences - Commenting and tick off the box next to "Always use Log-In Name for Author name". Probably should do that first...

Another option is to use a script to anonymize all the comments in the file, like this (free) tool I've created:

http://try67.blogspot.com/2008/11/acrobat-anonymize-comments.html