Dataset Search enables users to find datasets stored across thousands of repositories on the Web. Dataset Search is currently in Beta, with the greatest coverage in environmental and social sciences, as well as government data.
Provides census and survey data from the US and internationally and around topics such as the Current Population Survey, global health, US Census & GIS mapping, population and the environment, time use, health, and higher ed.
"Data archive of more than 250,000 files of research in the social and behavioral sciences. It hosts 21 specialized collections of data in education, aging, criminal justice, substance abuse, terrorism, and other fields."
The World Bank's Open Data initiative is intended to provide all users with access to World Bank data. The data catalog is a listing of available World Bank datasets, including databases, pre-formatted tables, reports, and other resources.