I start by going to Content Tools -> Tags and it lists a number of articles that have been tagged. In this case, the articles are all pages that have been created or updated but not published.
When I click on the link showing the number of articles it provides a list, however the number of articles shown in this list is less than the number of articles identified as tagged.
Also, when I go to Bulk Operations and filter on the tag I see the same number of articles shown.
So, I presume that the list of articles shown under Tags is missing some.