Behavioral targeting firm Revenue Science has expanded into search retargeting, allowing advertisers to extend the reach of their search campaigns by targeting advertising to visitors who came from search engines but did not convert, reports AdWeek. The company, which charges on a cost-per-click basis, says a 75-campaign test by 40 advertisers resulted in a 40 percent drop in customer-acquisition costs.

Using cookies to record the search terms used, Revenue Science applies that information to show those users relevant ads with new offers when they visit sites in its advertising network.

"It shifts some of the power from a rent to an own model," said Omar Tawakol, Revenue Science CMO. "You rent a click and you have to keep renting that click [from a search engine]. This moves it to an ownership model."