Effective messaging is crucial for communicating with a large user base, as it can be stressful and have unintended consequences. To craft an effective message, consider the recipient, what you want to communicate, the next action, tone, timing, consistency, and medium. Context is key, and companies should tailor their messages to specific groups or individuals. A messaging exercise, such as sending a mobile app notification, can help identify areas for improvement. Various approaches, including targeting specific groups, leaving permanent messages in the app, and using a consistent tone, can enhance message effectiveness. A remarkable message, like Derek Sivers' receipt email, can spark engagement, while an appropriate message, like Google's feature notifications, caters to individual needs. A consistent message is essential for building trust, as seen with Spotify's customer communications. Timing is also critical, as Twitter's mobile app notification demonstrates. Ultimately, it's not just about the words used but also when, where, and how they're delivered.