The curve of interest is a concept used to keep users engaged over time. It starts with grabbing the user's attention, then builds excitement and interest, and finally provides a satisfying conclusion. Here's how it works:

• The hook: This initial stage grabs users’ attention. It's designed to spark curiosity and excitement, making users want to engage with the content or activity. For example, a focus app like Forest introduces a fun and unique concept like growing a virtual tree while staying focused.
• Rising interest: As users continue, their interest is maintained and increased through engaging content, challenges, and rewards. This stage involves providing new and varied experiences that keep users motivated and involved. For instance, Forest offers visual progress, unlockable features, and rewards for consistent focus sessions.
• Climax: This is the most exciting part of the experience, where users reach a significant milestone or complete a major task. It provides a sense of achievement and satisfaction. For example, users might feel a peak of excitement when they grow a large, diverse virtual forest or earn enough points to plant a real tree.

By following this curve, your product can keep users engaged and motivated from start to finish.