Game companies use five components-four core components and one complementary one-in a 5Cs model to ensure the control and development of virtual worlds. A multidisciplinary review of the literature reveals that game companies make use of copyright, codes, creativity, and community to do this. They use the contract as a complementary component to reinforce their control over the four basic components and to compensate for the lacunae they present. In order to examine the extent to which game companies use the contract in this way, an analysis is performed of all contractual documents from a sample of 20 virtual worlds, providing evidence of general trends and emphasizing any differences between the virtual worlds in terms of the business and gaming models sought by each game company. An explanation is provided of why these contracts do not constitute a sustainable model for the game companies, given the high level of legal insecurity they present. Some basic recommendations can be made in order to improve the sustainability of the 5Cs model by modifying these contracts in such a way that they are enforceable and by matching their content with appropriate business and gaming models. This could lead to further studies aimed at providing answers to some of the intriguing issues affecting scholars and practitioners.