City-Data claims to have collected and analyzed much interesting data from numerous sources on as many U.S. cities as they could:

"We have over 74,000 city photos not found anywhere else, graphs of latest real estate prices and sales trends, recent home sales, home value estimator, hundreds of thousands of maps, satellite photos, stats about residents (race, income, ancestries, education, employment...), geographical data, state profiles, crime data, registered sex offenders, cost of living, housing, religions, businesses, local news links based on our exclusive technology, birthplaces of famous people, political contributions, city government finances and employment, weather, tornadoes, earthquakes, hospitals, schools, libraries, houses, airports, radio and TV stations, zip codes, area codes, air pollution, latest unemployment data, time zones, water systems and their health and monitoring violations, comparisons to averages, local poverty details, professionally written city guides, car accidents, fires, bridge conditions, cell phone and other towers, mortgage data, business storefront photos, a forum and a social network with 1,000,000 registered members and 18,000,000 posts, blogs, 5,000 user-submitted facts, 27,000 exclusive local business profiles with photos, restaurant inspection results, and more demographics."