What you did not post, Facebook may still know

In shaping its targetted advertising strategy, Facebook is no longer relying solely on what Facebook users reveal about themselves. Instead, it is tapping into outside sources of data to learn even more about them.

In shaping its targetted advertising strategy, Facebook is no longer relying solely on what Facebook users reveal about themselves. Instead, it is tapping into outside sources of data to learn even more about them - and to sell ads that are more finely targeted to them. Facebook says that this way, marketers will be able to reach the right audience for the right products, and consumers will see advertisements that are, as the company calls it, 'relevant' to them.

In late February, Facebook announced partnerships with four firms that collect lucrative behavioral data, from store loyalty card transactions and customer e-mail lists to divorce and Web browsing records.

They include Acxiom, which aggregates data from a variety of sources, including financial services companies, court records and federal government documents; Datalogix, which claims to have a database on the spending habits of more than 100 million Americans in categories like fine jewelry, cough medicine and college tuition; and Epsilon, which also collects transaction data from retailers.

Acxiom and Datalogix are among nine companies that the Federal Trade Commission is investigating to see how they collect and use consumer data.

Facebook's fourth partner is BlueKai, based in Cupertino, Calif., which creates tracking cookies for brands to monitor customers who visit their Web sites. That data can be used to show an advertisement when those users log on to Facebook.

'Our goal is to improve the relevance of ads people see on Facebook and the efficacy of marketing campaigns,' Gokul Rajaram, product director for ads at Facebook, said on Friday.

Targetted advertising has important implications for consumers. It could mean seeing advertisements based not just on what they 'like' on Facebook, but on what they eat for breakfast, whether they buy khakis or jeans and if they are more likely to give their wives roses or tulips on their anniversary. It means what people don't reveal on Facebook may still be inferred from online and offline proclivities.