Acquisition of online advertising exchange expands Yahoo's advertising reach Yahoo will buy the remainder of online advertising exchange Right Media for $680 million in stock and cash, Yahoo said on Monday.The portal giant bought a 20 percent stake of Right Media in October for $45 million and now plans to acquire the remaining 80 percent, it said.Right Media offers advertisers and sellers of ad space a real-time marketplace to buy and sell display advertising on Web sites. The move expands Yahoo’s advertising reach beyond its own network of sites. It comes on the heels of Google’s planned $3.1 billion acquisition of DoubleClick announced this month as consolidation in the online advertising segment continues.New York-based Right Media was founded in 2003 with investment from Yahoo and others.Yahoo didn’t say Monday morning when it expects to close the deal. Technology Industry