Acxiom Corp. knows a lot about you. It has scoured public records for how many cars you own and what your house is worth. It has accumulated surveys that show if you are married and how many children you have.
And for years Acxiom sold that information to marketers eager to use it to send mailings and make telephone pitches to consumers most likely to buy. Now, the Little Rock, Ark., company is putting those hundreds of millions of bits of data in the service of customizing which display ads to show people browsing the Web -- a development that has raised red flags with some privacy advocates.
Acxiom's latest effort, announced yesterday, is one of the most aggressive in a broad push by Internet and online-ad companies to target display ads to specific groups of users.