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.

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Terry Semel

May 2001-June 2007: Yahoo made a sharp departure from Koogle when it looked to Hollywood for Terry Semel, who had spent 24 years at Warner Bros. A technology company run by a Hollywood suit?

At first, it worked. Semel was given credit for cutting corporate initiatives that made little sense and rationalizing business groups. He also diversified Yahoo's business away from strict dependence on display ads with alternative revenue streams such as premium services and classified listings. Semel saw Yahoo as a media play and pushed as hard as he could to realize that vision.

But the company lurched from one financial disappointment to the next. Semel was unable to come up with a way for this very first-generation Web company to stave off younger rivals. In particular, he was painfully slow to build a successful search advertising business and got left behind by Google.

One side note: Semel tried and failed to entice a fresh-faced Harvard dropout named Mark Zuckerberg to sell Yahoo something called Facebook. Had Zuck said yes, the tech landscape would look a lot different today.

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Jerry Yang

June 2007-January 2009: As Yahoo's co-founder with Jerry Filo, Jerry Yang had a special connection with the company. That's why he agreed to take over after Yahoo parted ways with Semel.

Fairly or not, Yang's legacy will forever be connected with the decision to reject Microsoft's $44.6 billion bid to acquire the company. Yang reportedly held out for $4 more per share than Microsoft was willing to pay and effectively killed chances for a deal. As the company's stock continued to slide, impatient investors bayed for Yang's head.

When he finally resigned as CEO, few on Wall Street expressed regret upon hearing the news. Of course, they also ignored the fact that Yang helped build one of the biggest Internet properties in the world.

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Carol Bartz

January 2009-September 2011: When it came to speaking her mind, Carol Bartz wasn't a shrinking violet. In fact, she was the sort of down home #$%! bad*&$ who let you know where she stood -- any time, anywhere, and on any particular issue.

Along with her extensive tech industry resume, Bartz's unusual frankness helped convince the board that Bartz indeed had what it took to get Yahoo back on track. But Bartz, a former Autodesk CEO, had no background in media and advertising - and here she was appointed to run a company build around media and advertising. Hello?

The strange denouement came when she announced the news in an all-staff email from her iPad: "To all, I am very sad to tell you that I've just been fired over the phone by Yahoo's Chairman of the Board. It has been my pleasure to work with all of you and I wish you only the best going forward."

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Scott Thompson

January 2012 to May 2012: This one is destined to become a Harvard Business case study one day. Scott Thompson, hired earlier this year, lost his job because of he fudged his resume, falsely claiming to have had a computer science degree. And like Bartz, he had zippo experience in media and advertising -- Thompson's previous stint was at online payment company PayPal.

But in his short time at the helm, Thompson was active. He pushed a controversial patent lawsuit against Facebook that most of Silicon Valley treated with disdain. And he orchestrated a massive layoff but raised questions for not really articulating how he intended to retool Yahoo to remain relevant in our increasingly Google-centric world.

But it was the bizarre inclusion of a phony academic credential which ultimately brought Thompson down. Any other company and you'd say, "Well, stuff happens." But given that it's Yahoo, one can be excused for wondering whether they built the place on the site of an ancient Indian burial ground.

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Ross Levinsohn

May 2012 to July 2012: It was a short reign for temporary CEO Levinsohn, who stabilized the company in the wake of Thompson's departure by, among other things, ending its fratricidal patent fight with Facebook. But his deep rolodex and online-media experience wasn't enough to make him more than a caretaker.

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Marissa Mayer

July 17, 2012-onward: Yahoo gave interim CEO Ross Levinsohn the cold shoulder and instead opted for start power by naming Marissa Mayer, one of Google's top execs, as its next CEO.

The appointment of Mayer, 37, is a big coup for Yahoo. She joined Google in 1999 as employee No. 20 and has been Google's most prominent female executive, often speaking at big tech conferences about Google's products. She is known as the person responsible for the look and feel of Google's most popular products -- not just its main search home page, but Gmail, Google News, and Google Images.

More recently, she was put in charge of Google's maps and location services. All told, she was behind the launch of more than 100 Google products and features, according to Yahoo.

What's still unclear: How this dyed-in-the-wool Googler will fare in the Yahoo snakepit. Hopefully she'll have better luck than Carol Bartz.

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