Google&39's Larry Page (right) has plenty of work now that Google&39's ruling trio of Eric Schmidt (left) and Sergey Brin has changed.

Back in 2001, Larry Page wasn't ready to lead Google's 200 employees. Ten years later, with 24,400 employees, Page takes control of a much more complex operation, and both still have much to prove.

Ready or not, it's Page's company now, following news that former CEO Eric Schmidt would be moving up and out of the way to assume a traveling statesman role as Google's public face. Page's longtime partner Sergey Brin will focus more on product and technology direction while Page assumes control of Google's overall strategy and financial performance, which is a similar working relationship the two enjoyed before Schmidt came on the scene.

For all who levy the one-trick pony accusation at Google these days, back then that's exactly what is was. Now not only does Page have to make sure that Google stays atop the search world, he needs to figure out a way to make Google relevant in social media, oversee a burgeoning mobile software platform, nurture an enterprise-software sales and support group, and figure out a way to keep Google's best employees from departing for Facebook, Twitter, Zynga, and the other darlings of the start-up world. Oh, and the government is watching.

But he is not one to be underestimated' the engineer who created PageRank with a keen mind for strategic concerns and a sense of what people want from Google. For example, he bootstrapped the Google Street View project by driving around Palo Alto, Calif., with a video recorder hanging out the side of his car.

He famously wrote in the letter accompanying Google's 2004 initial public offering that "Google is not a conventional company. Eric, Sergey and I intend to operate Google differently, applying the values it has developed as a private company to its future as a public company." Now that that ruling troika has changed, what's next for Page

Perhaps the most immediate change is that Page now holds the legal responsibilities of a CEO, responsible for Google's financial statements and accountable to the demands of any legal actions in which Google is involved. Like most companies its size, that's quite a few, and staying on top of all those considerations will sap a lot of time from Page's schedule.

The aforementioned 2004 letter was inspired by Warren Buffett's approach to management, and if Page adopts many of the Oracle of Omaha's tactics, he'll probably be all right. Yet while Google is far from broken as a financial and technical machine, Page's biggest challenge is the longer-term problems facing Google.

As noted in our 2011 resolutions for Google, in addition to the social-media concerns, it needs to successfully confront government regulators and ramp up its game in consumer software to match the Apples of the world. If Schmidt is free to concentrate on Google's external opportunities and threats, Page and Brin can tag-team Google's strategic and execution problems when it comes to product development.

Page also needs to figure out a way to make Google a more nimble decision-maker and more attractive place for those with entrepreneurial leanings. Google has experimented with alternative management structures that created autonomous teams, as it has did with the Google Wave team (perhaps not the best example from Google's point of view).

However, there's just no getting around the fact that young, talented engineers looking to make a score before they settle down aren't as attracted to working for Google has they once were five years ago, when Google was the place to be. While life at Google has hardly turned into sweatshop labor, there are alternatives to its particular brand of engineering playgrounds filled with gourmet food and volleyball courts.

Is Page merely a placeholder CEO, keeping the chair warm until another adult can be brought in to supervise It's certainly hard to imagine Google adding an external CEO at this point in its career, but an additional challenge for Page will now be succession planning and executive retention. For when the CEO is only 38, the experienced senior vice presidents who are invaluable when it comes to running the company can do the math and calculate whether their careers would be better served elsewhere.

In any event, it's his company now. When Page wrote that 2004 letter, he envisioned working as one leg of a stool alongside Schmidt and Brin for a long time. While Schmidt isn't exactly leaving, he is putting an outsized amount of responsibility on the back of a brilliant engineer who hasn't run a company in 10 years.

It's up to Page to prove that he's ready for the challenge of running one of America's most important and most targeted organizations. Google might wait a while before booking him on the Stephen Colbert show.

See also: &149' Schmidt: 'Adult supervision' at Google no longer needed &149' CEO shake-up at Google: Page replaces Schmidt &149' Eric Schmidt's letter on stepping down as CEO