Abstract
A virtual community is a composition of heterogeneous and independently designed subsystems, focusing on large-scale resource sharing, innovative applications and in some cases high performance computation. The sharing that we refer to is the direct access to computers, software, and data emerging in fields like science, industry and engineering. Several open issues need to be addressed in order to make possible these dynamic environments, such as how to manage access policies to coordinate resource sharing, how to establish a community, how to ensure that member communities respect community policies and so on
