You won't be able to see who has left a comment in a Pod if you have the Enter Email to view set to 'No' in the Share Settings when sharing the Pod.
All users that comment will be displayed as Anonymous viewers.
If you want to see who is viewing your Pod and commenting you can change the settings to 'Email only' or 'Verified email'.
We have a detailed article that reviews How to share a Pod and how to change the settings here: