Microsoft has received the go-ahead from both the US Department of Justice and the European Commission for its co-operative search deal with Yahoo.
Microsoft will now use its Bing search engine on Yahoo in exchange for the paid search results. Yahoo gets sales rights to advertising on its own and Microsoft's platforms.
"Although we are just at the beginning of this process, we have reached an exciting milestone," said Steve Ballmer, chief executive at Microsoft.
"I believe that together, Microsoft and Yahoo will promote more choice, better value and greater innovation to our customers as well as to advertisers and publishers."
The two estimate that the search engine switchover will take place this year, while advertisers and publishers should be transitioned in time for the holiday season, although the firms acknowledge that this deadline may be too tight.
Microsoft and Yahoo said that the transition to the new arrangement will be complete for everyone by 2012. A Search Alliance web site has been set up to keep customers informed of progress.
"This breakthrough search alliance means Yahoo can focus even more on our own innovative search experience," said Yahoo chief executive Carol Bartz.
"Yahoo gets to do what we do best: combine our science and technology with compelling content to build personally relevant online experiences for our users and customers."
The only countries still left to approve the deal are Korea, Taiwan and Japan, and it seems unlikely that objections will be raised.
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