Relevant NAICS and SIC codes for this industry:
It is important to know these codes in order to retrieve statistical information produced by the Census as well as search certain databases by these codes.
The links below will help you find other relevant codes you may want to identify. You can also find NAICS and SIC codes by looking at the industry information for a company in a database like Mergent Intellect.
One source you can use to apply NAICS codes is the Business Patterns database from the U.S. Census Bureau. This can help you determine what has been the trend in a particular industry from a National, County, Metro, and Zip Code perspective. Please note, however, that this will probably not include those establishments that are purely web-based.
You can also use NAICS and SIC codes to find Industry reports from First Research.