Facebook Expands Targeted Advertising Through Outside Data Sources - NYTimes.com

A different type of Facebook over-sharing

"In shaping its targeted advertising strategy, it 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 companies that collect lucrative behavioral data, from store loyalty card transactions and customer e-mail lists to divorce and Web browsing records."

Facebook Expands Targeted Advertising Through Outside Data Sources - NYTimes.com