Timeline of Microsoft and Yahoo talks

It took 18 months for Microsoft and Yahoo to work out a deal, a string of events that started as a proposed acquisition and resulted in a search ad and technology partnership.

2008

Jan. 31: Microsoft proposes acquisition of Yahoo for $31 a share. The bid is made public Feb. 1.

Feb. 11: Yahoo board of directors rejects the offer.

April 5: Microsoft CEO Steve Ballmer's ultimatum: If there's no agreement in three weeks, he will launch a hostile takeover.

April 9: Yahoo says it's testing Google's search-advertising service to display ads next to results from Yahoo's search engine. Microsoft cries foul on antitrust grounds.

April 26: Ballmer's deadline passes. No hostile takeover.

May 3: Yahoo CEO Jerry Yang and co-founder David Filo meet with Ballmer and Kevin Johnson, president of Microsoft's platforms and services division, in Seattle. Microsoft reportedly increased offer to $33 a share. Yang and Filo reportedly say Yahoo board wants $37 a share. Ballmer withdraws offer.

July 12: Yahoo reportedly rejects Microsoft offer to buy search business only..

Aug. 1: Yahoo board and top management survive attempts led by dissident shareholder Carl Icahn to wrest control.

Nov. 5: Google, facing potential fight with antitrust regulators, withdraws proposal for search advertising deal with Yahoo, which the latter had sought as an alternative to a Microsoft acquisition.

Nov. 17: Yang, who bore much criticism for the failure to reach a deal with Microsoft, says he will step down as CEO.

Dec. 4: Microsoft announces hiring of Qi Lu, a respected senior Yahoo executive, to be president of the Microsoft Online Services Group.

2009

Jan. 13: Yahoo names Carol Bartz to replace Yang as CEO. Bartz was a longtime CEO at Autodesk and one of the few women to head a major tech company.

Spring-summer: Periodic reports say the two companies are trying to craft some kind of deal centered on search advertising and technology. Ballmer says repeatedly that Microsoft is no longer interested in purchasing Yahoo, but was open to a search deal. Bartz says Yahoo is interested, but famously adds that she doesn't want to see Yahoo "pulled apart and left for the chickens."

July 29: Microsoft and Yahoo announce that they have reached partnership agreement on search.