The Secretive World of Selling Data About You

In fact, it’s unknown exactly how many data brokers operate in the United States, because so many keep a low profile. Credible estimates range from 2,500 to 4,000. There are supergiants in the field—Acxiom, Experian. But there are myriad smaller companies that few have heard of: Exact Data, Paramount Lists, Datalogix, Statlistics.
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There’s a fast-growing market for what’s called “consumer scores.” Instead of a straight list of names, addresses, and other info, a consumer score is a computer-generated number that attempts to predict your likelihood to get sick, or to pay off a debt. Consumer scores are similar to FICO credit scores, but aren’t regulated as to what factors can be used and how transparent the score and its contributing factors are to the scored individual.
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Senator Edward Markey (D-Mass) introduced a bill last year called the Data Broker Accountability and Transparency Act of 2015. 
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StopDataMining.me, offers links and instructions to opt out of what it claims are the 50 top data brokers.

http://europe.newsweek.com/secretive-world-selling-data-about-you-464789
http://www.stopdatamining.me/
http://www.stopdatamining.me/master-list-data-broker-opt-out-links/