Hyper-Personalized Emails is the process of tailoring email content to individual users. It involves recognizing an individual's preferences, interests, and habits, and then using that information to present them with content that is tailored to their tastes.
A personalized email message will have a customized subject line, body text, graphics or pictures, and even offers based on user interests. Because it is so personalized to the recipient's preferences, it can be more effective at grabbing their attention than a "template" message might be.