Terry Semel's tumultuous tenure at Yahoo! (NASDAQ:YHOO) has been terminated. The colorful CEO who successfully steered the company through the bursting of the dot-com bubble is being dismissed, replaced by co-founder Jerry Yang. Semel will retain his role as board chairman, while Sue Decker is being promoted to company president.

In brief, Semel's gone because Yahoo! proved to be a square peg that didn't fit into Google's (NASDAQ:GOOG) round hole. If you want the whole story, pull up a beanbag chair and get comfortable.

So long, Semel
I defended Semel last week, arguing that Yahoo! needed a new cookbook more than a new chef. However, the writing was on the wall. The media outcry over Semel's stock-based compensation was too loud. The "no confidence" vote by dissenting shareholders during the company's annual meeting was too wide.

Unfair as it may seem, the witch hunt was starting to smell like Bob Nardelli all over again.

Like clockwork, you can expect a temporary pop in the share price this morning. Then things will settle down again, once the market realizes that Yahoo! is simply reshuffling executives. Just when you think the venom well's run dry, look for another primal scream if Semel's severance package includes a pricey golden parachute.

Yang is well-liked, and Decker is a rising star. However, they've been high-ranking executives at the company for years now. I doubt that swapping hats will make them dream up new ideas.

Yahoo! hopes that a statement this loud -- pulling the rug out from under its own CEO, in a supposedly friendly transfer of power -- will be enough to shake the company's rust off.

Semel's days were numbered. Three of the corporate chieftains singled out in my "4 CEOs to Go in 2007" column six months ago -- which included Semel -- have now been relieved of their duties. The fourth, XM's (NASDAQ:XMSR) Hugh Panero, is set to step down if his company is allowed to merge with Sirius (NASDAQ:SIRI).

Waxing positive
As ineffective as Semel's leadership has felt lately -- judging by recent flat financials and moribund stock ticks -- things could be far worse for Yahoo! Does anyone still use search engines like Lycos, AltaVista, InfoSeek, and Excite, which were the company's main competitive threats during the dot-com bubble days? OK, so Yahoo! is no Google. Is the market trying to tell me that steering Yahoo! to a profitable second-place finish isn't enough? Why are other non-Google players with popular CEOs, like IAC/InterActiveCorp's (NASDAQ:IACI) Ask.com and Microsoft's (NASDAQ:MSFT) MSN, given a free pass? The explosive paid-search market has room for plenty of players.

Semel also deserves some credit for Yahoo!'s successes. Minority stakes in China's Alibaba and Yahoo! Japan have made the company an overseas force. Acquisitions of edgy Web 2.0 companies like Flickr and del.icio.us, and the development of its own Yahoo! Answers, show that the company can be strong in areas where Google is not.

Stop thinking of Yahoo! in terms of Google
Yahoo! is in a funk, but how much of those blues derive from outsiders perpetually comparing the company to Google's gold standard? Think about it. Both companies report their quarterly results just days apart, making it even easier to pick out the laggard's shortcomings.

Yahoo! failed to beat Wall Street estimates in five of the last six quarters. Meanwhile, Google disappointed the prognosticators just once as a public company. But Google is a speedster, built around generating traffic and cashing in when it successfully sends those visitors off to a sponsor's site. Meanwhile, Yahoo! banks on keeping its visitors longer, making its individual page views less lucrative, and ultimately a slower grower in the paid-search revolution.

We hoist Google on our shoulders. We burn Yahoo! in effigy. Yet we never take the time to wonder why Yahoo! -- a site with more overall traffic than Google -- is valued at a fraction of Big G.

There's an investment opportunity there, of course. But if I went that way, I'd be falling into my own trap. Yahoo! banks on more than just paid search to bring home the bacon. It's an online service provider, too. Just look at the success of features as diverse as HotJobs and its Yahoo! Personals dating site. Better yet, those HotJobs employment listings have helped Yahoo! establish promising relationships with the websites of 400 different daily newspapers.

Sure, the company's upgrade to its paid-search product is more Google-like than its original incarnation. Given the choice, of course it would want to be a speed demon like Google. But Yahoo! is a different company, and it should be tempered with different expectations.

Unless that changes, I give the Yang honeymoon nine months, tops.

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Longtime Fool contributor Rick Munarriz admits to being critical of Semel in the past. He does not own shares in any of the stocks in this story. Rick is also part of the Rule Breakers newsletter research team, seeking out tomorrow's ultimate growth stocks a day early. The Fool has a disclosure policy.