World Map is a free program developed by the Center for Geographic Analysis at Harvard University. World Map is designed to enable creation, visualization, and exploration of geographically referenced information. In other words, you can build some great mapped data visualizations on the service.
Target Map is a service that allows anyone to create mapped displays of data sets. Users of Target Map can import and map their own data sets, use data sets from other users, use data sets found online, or manually input data onto a map.