When defining success metrics for Facebook Messenger Kids, it's important to consider the goals and objectives of the product. The primary goal of Messenger Kids is to provide a safe and secure messaging platform for children, while also giving parents control over their children's online interactions. To measure the success of Messenger Kids, we can look at a variety of metrics, including: - User engagement: We can measure engagement by looking at the number of active users, the frequency of use, and the duration of each session. We can also track the types of content that users are sharing and the interactions they're having with each other. - Parental control usage: We can measure how many parents are using the parental control features, such as setting up accounts for their children, approving contacts, and monitoring their children's activity. - Feedback and reviews: We can gather feedback from both parents and children to understand how they're using the product and what they like or dislike about it. We can also monitor reviews and ratings in app stores and social media. - Safety and security: We can measure the effectiveness of safety and security features, such as reporting and blocking tools, by monitoring the number of incidents and the response time for each incident. By tracking these metrics and adjusting the product based on the insights gained, we can ensure that Messenger Kids meets its goals of providing a safe and secure messaging platform for children while also satisfying the needs of parents.