How To Find Subscribers Without Any Tags
You know how to tag your subscribers, but what about the subscribers that might not have any tags? Here's how to find them:
First, Create a New Segment:
Select 'All Subscribers' as your first Filter Group:
Add a new Filter Group, and select "Matches: None."
Add a new filter for every tag in your account.
Voila! Anyone left in this segment does not have a tag!