With subscriber preferences, your subscribers can choose exactly which content they want to receive. This gives you insight on which of your content topics are the most popular, and can also help you reduce unsubscribes. 

Set up your subscriber preferences on the Subscribers page by adding in different Topics of Interest. Each topic will match to a one tag and you'll be able to add up to 10. 

Your subscribers will be able to opt-in or opt-out of the topics you've set in their subscriber profile. 

For more information on how to set this up, please read this support article.