I only knew about the concept of Growth Marketing AARRR, but now I know that the retention funnel also has a narrow sense and a broad sense. As I learned that segment and cohort are frameworks for classifying customers based on the concept of time, I realized I lack knowledge myself. It is interesting that problems are solved after classifying customers based on these criteria, and I feel a strong desire to try it out in practice. Also, if a bootcamp were to be held where marketing actions are established after analyzing actual raw data, it would be interesting.