Facebook Reels: Launch Rationale and a North-Star Metric with Guardrails

You are a product manager at Meta working on Reels in the Facebook app, the format for short vertical videos. Answer two related questions: why did Facebook launch Reels, and how would you define its success metrics? ### Clarifying Questions - Should Reels be judged as a surface on its own, or by what it adds to Facebook as a whole? - Which stage are we measuring: the early period when adoption matters most, or a mature product where retention and monetization matter more? - Is there a priority audience, such as younger adults, or does success apply to all Facebook users? - Do Reels that creators cross-post from Instagram count toward Facebook Reels activity? ### Part 1 — Why Facebook Launched Reels Explain the strategic reasons behind adding Reels to Facebook: what was changing for viewers, creators and competitors, and how the product serves Meta's mission and business. ```hint Look at every side of the market Consider how viewing habits were changing, where creators were choosing to post, and what Facebook risked by not offering the format. A strong rationale names both a user reason and a business reason. ``` #### What This Part Should Cover - The shift in how people consume video and the competitive pressure behind it - What Reels offers viewers, creators and advertisers - How the launch fits Meta's mission and business model - The costs and risks Facebook accepted by launching it ### Part 2 — Defining Success Metrics Define how you would measure whether Reels on Facebook is succeeding: one north-star metric, the supporting metrics around it, and guardrails. Justify each choice and say which alternatives you rejected. ```hint Let the launch goal pick the metric Your answer to Part 1 should decide what success means. Watch for metrics that can rise while Facebook as a whole gets worse. ``` #### What This Part Should Cover - A north-star metric tied to the launch goal and compared with alternatives - Supporting metrics across viewers, creators and monetization - Guardrails for cannibalization of other surfaces and for content integrity - How to tell whether gains are incremental to Facebook ### What a Strong Answer Covers - A launch rationale grounded in user behavior and competition, not a generic "to increase engagement" - An ecosystem view of creators, viewers and advertisers and the actions each takes - Consistency between the stated launch goal and the chosen north star - Guardrails that protect Facebook's social core and the quality of recommended content - A measurement plan that separates growth of Reels from growth of Facebook overall ### Follow-up Questions - Reels watch time rises sharply but total time spent on Facebook stays flat. Is Reels succeeding? - The number of people creating Reels falls for two months while viewing keeps growing. How worried are you, and what do you check? - Your north star improves while comments and shares between friends in Feed decline. What do you recommend to leadership?