Establish hooks to provide value and help people form healthy habits. The Hook Model:. External Trigger. Email, links, app icon. Action. Behavior done in anticipation of a reward. Variable Reward. Predictable rewards aren't intriguing. Investment. User puts something into the product: time, data, effort, social capital, money. Improves the experience for the next go-around. Inviting friends, stating preferences, building virtual assets, learning to use new features. Internal Trigger. Build products to help people do the things they already want to do, but for the lack of a solution, don't do. Technology can enhance lives to improve relationships, make us smarter, and increase productivity. Connect the user's problem to a solution frequently enough to form a habit. Hooked users become brand evangelists.