1998: Google Inc. founded.
1999: Semel leaves Time Warner Inc., where he ran the movie business and oversaw box office hits such as "Lethal Weapon."
Feb. 27, 2001: Yahoo board fires CEO Timothy Koogle, passes over President Jeffrey Mallett, and conducts outside search.
May 1, 2001: Semel becomes Yahoo's chairman and CEO.
February 2004: Semel says Yahoo will stop using Google search results and rely on its own technology.
August 2004: Google has initial public offering and ends first day of trading with a market capitalization of $23 billion, compared with $39 billion for Yahoo.
September 2006: Semel warns Yahoo will miss third-quarter financial targets, blames decline in automobile and financial services advertising.
October 2006: Google announces $1.65 billion all-stock deal to buy video-sharing site YouTube, one of the Internet's rising stars.
Dec. 5, 2006: Semel overhauls management. Chief Operating Officer Dan Rosensweig and Lloyd Braun, who oversaw Yahoo's media division, resign.
Feb. 5, 2007: After months of delays, Semel unveils "Panama" advertising system, which supposedly distributes ads better.
April 13, 2007: Google agrees to pay $3.1 billion in cash to acquire ad-management technology company DoubleClick Inc.
April 30, 2007: Yahoo acquires online advertising exchange Right Media Inc. for $680 million. Regulatory filing puts Semel's 2006 compensation at $71.7 million, more than any other CEO at the 386 publicly held companies covered in an Associated Press analysis.
Early May, 2007: Media reports say Microsoft Corp. is contemplating a takeover of Yahoo, temporarily boosting shares. Deal never materializes.
May 15, 2007: Yahoo hires investment banker Blake Jorgensen as chief financial officer, replacing seven-year CFO Susan Decker, who's promoted to oversee advertising operations.
Early June, 2007: Angry over Semel's $71.7 million 2006 pay package, investment groups recommend opposing the re-election of board members who sat on the compensation committee.
June 8, 2007: Last official day for CTO Zod Nazem, the 11-year veteran who led the development of Panama.
June 12, 2007: Semel hosts shareholders meeting and says Yahoo "has staked out a strong competitive position," but stock has dropped 18% since last year's meeting.
June 18, 2007: Semel ends six-year tenure as CEO, hands over the reins to Yahoo co-founder Jerry Yang. Susan Decker becomes president.
Source: Associated Press archives.