The document discusses user-generated content (UGC) in games. It defines UGC as tools within games that allow players to create their own content, such as character customization or level editing. This is different from downloadable content (DLC) which adds pre-made content. UGC gives games more replay value and lifetime value by exploiting player creativity. Examples provided are Minecraft, whose success was based on large-scale building, and LittleBigPlanet, which saw over 6 million user-generated levels created. The document argues that UGC, when implemented successfully, can greatly enhance games and engagement.