SUNNYVALE, California: Yahoo is to pay $680 million (€499m; £341m) for the remaining shares in online advertising exchange Right Media.

The web search giant already owns 20% of the firm - a stake bought last October - and it hopes the acquisition will make it "a partner of choice for advertisers and publishers" to expand its reach into social networking sites.

New York-headquartered Right Media, headed by former DoubleClick executive Michael Walrath, opened its exchange in 2005. It serves up banner ads and other formats to less trafficked parts of the web, unlike traditional premium ad networks which target busy sites.

Comments Yahoo ceo Terry Semel: "This acquisition is an important step in our long-term vision to build the industry's leading advertising and publisher ecosystem. We believe that Yahoo's open approach is a clear differentiator from others in the industry."

Yahoo has struggled to keep up with arch rival Google in recent months, while its much-vaunted Panama advertising search system failed to deliver a hoped-for boost in first quarter profit [WARC News: 19-Apr-07].

Google last month acquired DoubleClick for $3.1bn, a move that will also allow it to sell so-called remnant advertising on millions of less-trafficked web pages.

Data sourced from Financial Times online; additional content by WARC staff