MySpace's "interest-based targeting" system uses algorithms to comb MySpace profiles and members' blogs, and place users in groups according to their primary interest; categories include sports, fashion, finance, video games, cars and health.
Each group, which contains more than 3 million members, can then be further divided into hundreds of subcategories.
"We are blessed with a phenomenal amount of information about the likes, dislikes and life's passions of our users," Peter Levinsohn, president of Fox Interactive Media, told a Merrill Lynch investor conference on Tuesday.
"We have an opportunity to provide advertisers with a completely new paradigm."
The company told The New York Times its new targeting system has improved the likelihood that members will click on an ad by 80% on average.
While Fox is currently handling interest-based ad sales manually, the company plans to launch a Web-based automated system in November.