To See Your Subscribers' Ad Tracking Categories
Go to your "Subscribers" tab and click on "Subscribers."
Here, you can click the "Search" button to display your whole list. You can also enter some search terms first to find particular subscribers quickly.
Click on the name of the subscriber that you would like to see their ad tracking value for.
Under Subscriber Information you will see their ad tracking value on the left side of the page.
To find a group of subscribers with the same ad tracking value you can you do a search based on what would be in the ad tracking field using the "Search Option" drop-down menu on the "Subscribers" page. Once you type in the ad tracking value you want to search for just click "Search."
You will now see a list of all subscribers with the ad tracking value that you had searched for.