Geographic Information Systems (GIS) is a set of tools and data that can help researchers, policy-makers, and community members visualize, explore, and interpret information across space to understand spatial relationships, patterns, and trends. A map is created with layers that allows the user to find text information (demography, buildings, etc.) when a particular place on the map is clicked. GIS data can be combined with other data, for example, with census data from the US Census Bureau for exploration of policy issues.
There are many other tip sheets and tutorials available at the GIS@Tufts website: http://gis.tufts.edu.