To see the history of a specific tag, hover over it in the tag box. You’ll see who added the tag, how the tag was applied (in the document viewer, via mass tagging, for example), and when the tag was added.
To see a history of all the activity performed on a document, click the View document audit history icon.
Historical activity is broken up into two categories: Important changes and Everything else.
In order to see any of the information on this page, you must have the View document history permission enabled. See Managing users, roles, and permissions in a review database for more information.