Many countries gather and post extensive data on individuals, households, and businesses, broken down into a variety of categories. In the United States, you can find out how many people earn above a certain amount of money a year and live in a specific city or state – useful if you’re trying to figure out how big the regional market may be for a luxury product. Similarly, you can find out how many businesses operate in your industry and what their sales are in a specific city or state – useful if you’re trying to decide whether that city has a market big enough to warrant you moving into it.

If you want to use the Web to explore useful data compiled and posted by various agencies of the U.S. government, the main gateway into U.S. Census data on households and businesses. This site is your portal to U.S. data from the economic census (which goes out to five million businesses every five years) and the Survey of Business Owners. Fresh census data will be posted to this site in mid-2010, providing a solid base of data you can use for at least the next few years.

Another useful way to explore U.S. Census Bureau data, which has links on the navigation bar to the left.

Click on People to see breakouts and trends by age, sex, disability, education, employment, income, relationships, and so forth, or click on Business and Government to find out how many of which types of employers, manufacturers, wholesalers, or retailers are where.