Yahoo agrees to buy online ad exchange Right Media

Sunnyvale, Calif.—Yahoo announced Monday it has agreed to acquire Right Media, an open online advertising exchange, for about $680 million. Yahoo had bought a 20% stake in Right Media last October.

"This acquisition is an important step in our long-term vision to build the industry's leading advertising and publisher ecosystem," said Terry Semel, chairman-CEO of Yahoo, in a statement.

The deal also puts Yahoo head-to-head in the ad exchange business with rival Google. Earlier this month, Google announced an agreement to acquire DoubleClick, which launched its own online ad exchange April 4.

—Carol Krol