But Drummond's broadside struck many people as hypocritical. For one thing, Google itself dominates the Web search landscape, with nearly 70 percent of the market. For another, Google C.E.O. Eric Schmidt has floated the idea that Yahoo, its closest rival, could outsource its search business to . . . Google.

"Google's argument is somewhat facetious, given their market position," said Roger Kaye, president of research firm Endpoint Technologies. "It's kind of like the pot calling the kettle black."

Antitrust lawyer Glenn Manishin of Duane Morris, a veteran of Microsoft's competition battle with the Department of Justice, said links between Google and Yahoo would be "much more problematic" than a Microsoft-Yahoo merger.

Indeed, Google's near monopoly on Web searches is one reason the company should secretly favor a Microsoft-Yahoo merger, experts said. That deal would deflect regulatory attention away from its own market dominance.

While the U.S. Federal Trade Commission has approved Google's proposed $3.1 billion acquisition of digital advertising giant DoubleClick, European regulators have not.

If Microsoft's move on Yahoo is so good for Google, why is it pursuing a deal? Because, Cowen and Co.'s Friedland said, a merger is the "least bad alternative" for Microsoft C.E.O. Steve Ballmer.

UBS' Schachter summed it up. "This merger is fraught with risk for both Microsoft and Yahoo," he said. "But what other choice do they have?"