When the welcome email is sent to your subscribers, they'll be asked if they'd like to personalize their interests. By personalizing, subscribers explicitly tell us their interests, thus we call these explicit interests! This is one way your subscribers can receive personalized content.
There will be some in your audience who don't personalize. You might wonder how Cerkl personalizes content for these folks. Not to worry! Cerkl uses the same technology as Netflix to discover your audience's implicit interests, which are the interests your audience haven't told us about but have shown us by interacting with certain content. Since Cerkl knows what your audience clicks on, it can decipher their interests and begin to tailor newsletters toward these interests as well! This is how Cerkl's software still allows you to send personalized content to subscribers who have not personalized their interests!
So let's say one of your subscribers, Bob, selected "finance," "business," and "retirement" as some of his interests while personalizing. These are his explicit interests, so he'll receive content about these subjects. However, Bob has recently clicked on tons of food-related content! He's looked at all kinds of recipes, checked out news about restaurants, and has looked for healthier alternatives in his diet. Cerkl is aware of all this clicking. And by doing so, Bob has implicitly shown Cerkl his interests in cooking, restaurants, and healthy eating. Thus, Bob will begin to see more stories related to these interests in his newsletters!