You can segment your listeners across all feeds inside your Hello Audio account.
On the listener's page, find the Tags area. You can click on the listener's email address inside a feed, or you can head to "My Listeners" and click on the listener there.
Type your tag in the text box and hit enter to add it. You can remove a tag by clicking X. Click "Save & Return" when you're finished adding tags.
A few related features and help docs: