Opinion: Mayer is inheriting a major mess at Yahoo By Herb Greenberg, CNBC.com Maybe the choice of Marissa Mayer as Yahoo's CEO boils down to this: They've tried one legendary CEO after another, with a company founder thrown in, and none of them have worked. As a result Mayer, who has no experience running a company -- never mind a troubled $5 billion company in need of a turnaround --probably has as good a shot as any. But while the opportunity for someone like her is tremendous, so is the challenge. Like most rocky corporate situations, Mayer is likely to encounter a bigger mess than she could imagine. And whatever she wants to do will likely be costly and take an enormous amount of time, with this caveat: Unless the goal is further breakup the company to concentrate on its core search business -- as Yahoo morphs back into a tech-centric company. Otherwise, the reality is this, as one former Yahoo exec told me: Yahoo is a sprawling company with the complexity of operating in almost 60 languages and a larger number of markets, being a media and a tech company. They have 14,000 employees. I and a bunch of other current and former execs have always wondered how much more efficient and effective the place would be at two-thirds that size. Under 10,000 and it's more profitable and a better competitor. Will Marissa make that hard call if six others have had that chance and flinched? Good question, but wait -- there's more: Their search deal with Microsoft is underperforming and the guarantees are expiring. Maybe Marissa is actually ideal to optimize this deal because of her search experience, but I doubt it - she was never on the advertising side at Google. Always a product-design focus," the former exec said. And aside from leading the charge with Google's purchase of Zagat, it's unclear what experience she has with acquisitions (let alone divestitures.) That may be a good thing: Maybe under Mayer Yahoo won't overpay for acquisitions. Then again...this is Yahoo, Silicon Valley and the land of good and plenty. We've come to expect anything, including the outside chance of Mayer succeeding. Mayer has 100 days -- or less -- to prove herself 10 CEOs who turned around companies Can Marissa Mayer turn around Yahoo? 10 short-lived CEO terms