This site collects data from publicly accessible sources and has aggregated them. In the past, it was usually your financial, employment, and address information. Now, it seems these companies have mined social media sites to retrieve non-financial information.
If you have a credit card, taken out a loan, own a title to a house or car, asked for phone or utility service, use any social media site extensively, or been employed at any large company, most of this information can be accessed by these aggregators. The U.S. privacy laws are not strict enough to prevent this information from floating around.
2012 Convention Schedule
Steampunk Worlds Fair | Otakon