You are the PM of Messenger and notice a significant drop in DAU. How would you investigate the cause?

Focus on outlining a structured approach to diagnose the drop in Daily Active Users (DAU) for Messenger. Start by identifying key metrics and data sources that could provide insights, such as user engagement patterns, retention rates, and churn analysis. Discuss how you would segment the user base to identify if the drop is affecting specific demographics or regions. Consider external factors that could influence user behavior, such as market trends or competitor actions. Finally, emphasize the importance of formulating hypotheses based on your findings and suggest potential follow-up actions or experiments to validate these hypotheses.