Yahoo has responded to Google's DoubleClick acquisition with a purchase of its own, albeit on a smaller scale, reports The New York Times.

The search giant just purchased the other 80 percent of Right Media for $680 million. Yahoo purchased an initial 20 percent stake in the company last October and was using its marketplace platform for ad placement on sites.

The deal gives advertisers more options right off the bat as Yahoo opens up all non-premium inventory to the system. Publishers will be able to use it to sell space on their sites alongside Yahoo's space.

Yahoo CEO Terry Semel expects the deal to boost revenue as it makes non-premium inventory available. The company is coming off a disappointing first-quarter earnings report, even with the addition of the much-hyped Panama search ad system.

About 1,000 publishers currently use the Right Media platform.