Harvard University’s Center for Geographic Analysis (CGA) has created Harvard WorldMap, an online open-source mapping platform developed to lower barriers for scholars who wish to explore, visualize, edit, and publish geospatial information.  WorldMap was created to provide a mapping platform that supports large datasets that also allows collaboration.  Anyone can create their own online mapping portal, upload large GIS layers and overlay them with other layers, and control access to their data.  Check it out!