In recent years, more and more game manufacturers have launched "service-based games" to extend the life cycle of a game, and provide new content for players every other time to maintain attention, such as "Fortress Night", "Destiny" and "Whole Territory Blockade 2" just launched by Ubisoft. In a recent interview with IGN, Yves Guillemot, Ubisoft CEO, said that making service-based games is not just about making money. "We have spent a lot of time and energy in creating a new universe, world, city, that is to say, to give players more chances to stay in the world longer, because there are more different Gameplay content waiting for players to share with their friends. If (players) can continuously improve their experience and ability in a game, why do they have to repeat their work every year (in different games)? For Ubisoft, upgrading a game can provide ____________.