Our Terms of Service and Privacy Policy have changed.

By continuing to use this site, you are agreeing to the new Privacy Policy and Terms of Service.

These data miners know everything about you

Gathering your personal information to sell to marketers, insurers, employers and anyone else who wants it is big business. Here are some of the key players.

1 of 5
Who they are: The oldest and the biggest data aggregator out there, Acxiom says it has more than 32 billion data records. If you get direct-marketing mail, phone calls from telemarketers, offers by e-mail or ads targeted to you online, there's a pretty good chance the company behind it looked up information about you on Acxiom.

Founded in 1969 and based in Little Rock, Ark., Acxiom runs a vast collection of businesses ranging from background screening to social media marketing. Only rival ChoicePoint does anything close to the scale of Acxiom's business.

What they know: Pretty much everything. The company tracks all kinds of personal information, from your Web behavior to your Social Security number and your finances. It buys information from many other data aggregators, privacy experts say, so it has all of the details every other data miner has about you -- and it has more information individually than any other company.

"Acxiom is Rome," said Pam Dixon, executive director of World Privacy Forum. "All roads lead to Rome."

How to opt out: It's more complicated than you might think. To opt out of online advertising, click here.

To stop getting direct mailings and to take yourself off of Acxiom's other directories, you need to fill out an online form. The company will then snail mail you another form that you need to send back for "processing."

NEXT: Rapleaf
Last updated December 16 2010: 5:18 PM ET
More Galleries
Driving the ultimate in '50s Mercedes-Benz style The SC was the car that re-introduced Mercedes-Benz as a global luxury car icon. More
Driving the world's first car Driving a replica of the 1886 Benz Patent Motorwagen, the first internal combustion automobile. More
Your guide to Cyber Monday sales This year, more Cyber Monday sales than ever start well before Monday. Here's where to shop if you don't get your fill on Black Friday. More

Special Offer