The landmark partial merger between Yahoo and Microsoft has finally come to fruition, following regulatory approval from the U.S. Department of Justice and EU antitrust authorities.

Microsoft’s Bing search engine is set to take over search functions at Yahoo’s central search site by the end of 2010, a move that will push Bing’s total market share from 10 percent to nearly 30 percent; nearing the all-important one-third mark that search engine optimization (SEO) experts say will make the new conglomerate a solid alternative to Google.

However, PC World writer Jeff Bertolucci warns that Yahoo could be on the way out as a web portal, complicating the picture somewhat. Bertolucci asks "so will the Bing deal help Yahoo regain that lost [market] share? I don’t see how it could. Microsoft is the innovator here, the aggressor with the clever search engine that’s gaining market share – albeit slowly and at significant expense to Redmond."

Whatever happens to Yahoo, search engine optimization (SEO) analysts agree that the field is likely to be radically altered by the deal when it goes into effect.