The multi-year deal will pair Yahoo's Right Media ad exchange with the targeting prowess of WPP's 24/7 Real Media, giving WPP agencies a more effective system for buying mass quantities of display inventory worldwide.

WPP's GroupM media shops will be the initial benefactors of the partnership, which has two facets: Technology integration and a boost in inventory scale.

On the tech side, the two companies are developing a media trading platform that connects to the Right Media Exchange. GroupM agencies will be able to access the platform directly through 24/7 Real Media and plug in various targeting options--and then be able to execute buys on the exchange accordingly.

According to GroupM CEO Irwin Gotlieb, the partnership gives the group's agencies and clients "an advantage in securing more relevant, high-quality inventory."

Ryan Jamboretz, director of corporate development at GroupM, agrees. "It's no secret that we buy a good amount of media through 24/7," he said. "This only improves the product by allowing us to do things like behavioral and retargeting on a larger scale." Because GroupM agency clients were mostly large advertisers in search of massive audience segments, fulfilling their inventory needs quickly and with a simple buy was sometimes challenging, he added.

To address that issue, the partnership also includes a joint inventory marketplace populated by ad units from 24/7's Global Web Alliance, and Yahoo's owned and affiliated networks. Third-party publishers would also be invited to join as the marketplace was built out.

"It's like the 24/7 Alliance network has grown massively through the flip of a switch," Jamboretz said. "And a good thing about this approach is that we can implement it just by communicating to our people the improvement, and the benefits of buying ad network space this way. There's no major internal rollout plan needed."

The deal had been in the works for some time, according to Mike Walrath, senior vice president of Right Media and Yahoo's advertising marketplaces group. "We've had a long-standing partnership with WPP, but given the ad exchange and ad network developments over the past year, this was an obvious place for the companies to come together and spend some time."