High Quality Content by WIKIPEDIA articles! Various ways of operationalizing or measuring sustainability have been developed. During the last 10 years there has been an expansion of interest in SDI systems, both in industrialized and, albeit to a lesser extent, in developing countries. SDIs are seen as useful in a wide range of settings, by a wide range of actors: international and intergovernmental bodies; national governments and government departments; economic sectors; administrators of geographic or ecological regions; communities; nongovernmental organizations; and the private sector. SDI processes are underpinned and driven by the increasing need for improved quality and regularly produced information with better spatial and temporal resolution. Accompanying this need is the requirement, brought in part by the information revolution, to better differentiate between information that matters in any given policy context versus information that is of secondary importance or irrelevant.