Since unveiling its Bing search engine earlier this year, Microsoft has slowly gained market share and with an announced partnership with Yahoo, the distance between Google and a Microhoo search engine seems that much smaller, making it more important for companies to focus their search engine optimization on more than just Google.

But first Microsoft and Yahoo must convince regulators in the U.S. that the deal does not break antitrust laws, according to the Associated Press.

The proposed Microsoft/Yahoo deal wouldn’t create a monopoly considering Google controlled 64.7 percent of the market in July, according to comScore. Still, the AP notes that the Department of Justice is not a fan of duopolies either.

"If the traditional antitrust doctrines are followed, it is going to be hard for the authorities not to challenge this deal, unless some conditions are placed on the parties," Matthew Cantor, a New York attorney specializing in antitrust law told the wire service.

Although Microsoft and Yahoo hope to have their deal finalized by the beginning of 2010, it doesn’t appear that most companies are on board with the new search engine combination. A study last month from ClickZ found that 63 percent of firms said that despite the agreement, they don’t plan on increasing their search spending with Microsoft or Yahoo.