This paper is based on the application of the “Social World’s” theory created by Shibutani to the worlds of knowledge society, cyberspace, d-Knowledge CommonsEcosystem.1 Knowledge society will be presented as the social world and cyberspace as the sub-social world with the d-Knowledge Commons Ecosystem as the sub-world of cyberspace. This theory will open discussion about activity, boundaries,arenas and values of each social world/sub-worlds. However, the main intention ofthis paper is an introduction to a discussion about the sub-world of d-KnowledgeCommons Ecosystem as an example of one of the most striking sub-worlds within cyberspace trying to answer the question: why do we need social worlds while talking about d-Knowledge Commons Ecosystem? This paper is to be divided into fiveparts: 1. Activity, 2. Boundaries, 3. Arena, 4. Values, 5. Conclusion.