This is a segmentation where you analyze your audience on their behavior.
It includes:
However, you can take a step further by creating segments based on their interaction with your brand. You can consider here metrics like their purchase behavior (which products they prefer to buy, how regularly, average order value), brand loyalty, engagement with previous emails, and website interactions.
For example, if a customer purchases products from a specific category regularly, send them an exclusive offer for these products.
Take into account also which emails specific groups of subscribers open and when, how much time they spend reading them, etc.