The document discusses gamification and user engagement in social games. It notes that while social games can appear very engaging, the average social game has low retention and engagement rates. Only the top games are truly good at keeping users engaged over time, similar to top websites. The document cautions against seeing gamification as a magic solution, as building engaging games and game mechanics is very difficult. It provides some suggestions for effective uses of game mechanics, like using levels to structure content or processes, and emphasizes the need for testing, learning from failures, and iteration.