data.gov was launched in 2009 under President Obama's Open Government initiative in order to increase public access to government databases, statistics and publications. This site includes publicly-available information provided by federally funded agencies, including NASA, but also continues to grow due to user suggestions and feedback. Notice that a particular federal agency doesn't have a site or data included in data.gov? Let data.gov know!
Users can search or browse data.gov via three catalogs: the "Raw" Data Catalog - downloadable documents in XML, CSV, and other file formats; the Tool Catalog - links to agency-specific websites, applications or tools; or the Geodata Catalog - links to various image maps, historical data sets, and other geospatial information. Click on any catalog's tab to select it (the "Raw" Data Catalog is selected below) and narrow your search by agency, category, or keyword, or browse through all of the available information.
data.gov also links to state and local data sites similar to data.gov. At present, few such sites are available.
data.gov notes that by accessing datasets or tools offered on data.gov, users agree to the Data Policy, which users should read before accessing any dataset or tool. The policy includes information on privacy, security, and public information.