"SEDAC’s mission is to develop and operate applications that support the integration of socioeconomic and earth science data and to serve as an "information gateway" between the earth sciences and social sciences." from website
This resource includes a data resource directory for environmental and demographic topics.
SimplyMap is a web-based mapping application that lets users quickly create professional-quality thematic maps and reports using powerful demographic, business, and marketing data. SimplyMap turns complex data into valuable information that is easily accessed through an innovative and user-friendly interface.