Facebook Refines Ad Targeting - NYTimes.com Bought granola at the supermarket lately? Expect to see an ad soon on your Facebook page for something that fits your granola-buying profile. Facebook on Wednesday rolled out a long-anticipated and potentially lucrative way to show highly targeted advertisements to its users. What consumers have bought in the past, online and offline, is the best predictor of what they are likely to buy again, marketers say. Facebook has partnered with four data companies that track, to varying degrees, online and offline purchase behavior: Acxiom, Blue Kai, Epsilon, and Datalogix. Optimal, a San Francisco-based company that helps brands target their advertisements on Facebook, said the new product would allow companies to more precisely aim messages at the right customers at the right time. A barbecue sauce maker, for instance, could target customers who buy meat every week. Facebook has been under intense pressure to grow advertising revenue, its chief money maker. The new product allows more fine-tuned targeting. In a blog post, the company said: "To date, advertisers have been able to show ads to people based on their expressed interests on Facebook. Now with partner categories, they can also show ads to people on Facebook based on the products and brands they buy across both desktop and mobile. Nate Elliott, an analyst at Forrester, called it "a smart step" but not enough to significantly improve targeted advertising on Facebook. "Since they lack the expertise to turn their own data into truly useful ad targeting, it makes sense to bring in third parties who have stronger experience bringing meaning to data," he said, adding: "The real marketing value in social media isn't in trying to market to people on social sites; it's in using data from social sites to power better marketing everywhere else."