But now that a deal has fallen apart, Google has emerged as the key beneficiary. Not only has the creation of a larger competitor been averted, Google may also reach a partnership with Yahoo to deliver some of its paid search listings. Google and Yahoo are hammering out the intricacies of a potential deal and also are sharing their plans with antitrust regulators, a person close to Google, who was not authorized to speak publicly on the matter, said. A Google deal would boost Yahoo's operating performance in the near term, but runs the risk of regulatory scrutiny over an alliance between the Internet's top two players. In a letter to Yang over the weekend, Ballmer warned that any deal between Yahoo and Google would be difficult to unravel and would preclude an agreement with Microsoft. Yang told Reuters the company would take care to structure any new efforts to "preserve as much (as possible) long-term flexibility for Yahoo, both operationally and strategically."