Interested in a broad range of U.S. social, economic, and demographic information on-line? The American Community Survey might be of use to you.
Every year, the U.S. Census Bureau conducts the Survey, asking three million of us about our income, occupation, place of work, health insurance, marital status, ancestry, citizenship, language spoken at home, disability, housing, etc. etc. etc. This information is compiled and presents a snapshot of life in the United States at any given time.
You can access the American Community Survey by going to http://factfinder.census.gov, then clicking on Data Sets (on the left side), and then American Community Survey. Or click here.
The Census Bureau publishes a series of online handbooks (.pdfs) on how to use the Survey. There are handbooks for general users, business users, teachers, media, state and local governments, and researchers.