The document discusses metagame design and reward systems that drive engagement. It defines a metagame as layering a rewards system onto an existing activity to motivate certain behaviors. Examples of metagames include collecting items, earning ranks in karate or scouting, and frequent flyer programs. The document provides a framework for metagame design including assigning points to actions, adding feedback and rewards systems using levels, leaderboards, and achievements, and facilitating viral outreach through social sharing. It concludes with tips for compelling metagame design such as creating a coherent experience, defining appropriate point systems, motivating different player types, designing shareable rewards, and using game pacing.