This question presents an intriguing combination of product management and technical abilities. Essentially, the interviewer seeks to gauge your capacity to both conceptualize a product feature and comprehend its implementation within a live product. Let's break it down: "Launch" signifies the introduction or execution of a feature, which necessitates project management and product strategy. "Reactions" pertains to the Facebook feature that allows users to express more than just a 'like' on a post; they can now respond with love, laughter, surprise, sadness, and anger. "Facebook" identifies the platform where this feature is utilized. Therefore, your response should outline the complete process of launching a feature like 'reactions' on Facebook, including planning, design, implementation, testing, and the final rollout. Important points to address include: Recognizing the user need for greater expressiveness (the rationale behind it) Designing the user experience (the aesthetic and emotional aspects) Collaborating with engineering for implementation (the method of execution) Conducting testing and collecting feedback Iterating and executing a full-scale launch (the public release process)