The Web Observatories are becoming common Internet practice. They are web sites targeting a community of practitioners, scientists or generally individuals within the context of a focused organization. Their goal is to inform, educate, facilitate the interaction and boost the collaboration of community members. Various existing technologies can be deployed for this purpose. Still, their integration into a coherent informational and collaborative environment remains largely ad hoc. In this paper we attempt to elucidate the concept "web observatory" and identify its characteristics and practices.