Update: Tag history has been overhauled. You can now clearly see what tags have been +added and -removed from a post within the tag history as well as the category for each tag and the rating history. To view the tag history of a post click on it and look for the history section within the sidebar.
Filter content you don't want to see with "-tag" in the search box. You may also blacklist posts with tags that you don't want to see by adding them to the blacklist within your options page. Don't show this message again.