Tim Koogle

1995-May 2001: Yahoo's first CEO Tim Koogle made black turtlenecks a tech exec fashion statement while Steve Jobs was still in exile from Apple. A 1998 Business Week profile called Koogle "the grown-up voice of reason" at Yahoo. Three years later, he stepped down, seemingly unable to do anything about the implosion of Web advertising as the dot com bubble burst.

Under Koogle, Yahoo paid billions for companies like Broadcast.com and Geocities. Those were the days when "counting eyeballs" was all the rage and tomorrow's horizon promised to be that much brighter than today's. All good until the reckoning came and investors wondered what Yahoo was really all about. Another problem: Koogle had a reputation for being a nice guy who had a hard time saying "no" to projects that sprang up willy nilly.

(Koogle is now on the board of Room to Read, a nonprofit that promotes literacy and library construction in the developing world.)

Click on for more of Yahoo's CEOs.

Editor's note: This slideshow was first published on May 13 as "Impossible dream? 5 CEOs who tried (and failed) to run Yahoo." It was updated on today, July 16, to reflect news of Marissa Mayer's hiring.