By now everybody knows about Kodak filing for Chapter 11 bankruptcy. The company’s stock is basically worthless, after peaking above $90 in the ‘90s. It now has twice as many retirees to which it’s paying pension benefits than it does employees. And Kodak owes its creditors nearly two billion dollars more than it could fetch in liquidation. There’s clearly a mess to clean up.

But there’s also a lesson to be learned from the company’s lost decade. Kodak has in many ways been caught in a perfect storm of market tectonics, those external forces that wreak havoc on growth and profitability. To wit:

Competition: Kodak invented the digital camera, all the way back in 1975. But the company neglected to see how it would redefine the future. Foreign competitors like Nikon, Fuji and Sony did, and they stole Kodak’s market share with increasing velocity.

Economic Factors: Not only had Kodak not anticipated how quickly the market would go digital, the 9/11 terrorist attacks decimated leisure travel and the picture taking that goes with it. Even as post-9/11 travel returned to normal levels, film purchases declined 10-15 percent annually in subsequent years. And the economic environment during the past four years exacerbated the problem.

Changing Dynamics: Film industry sales were expected to shrink 10% between 2008 and 2010. Kodak figured its own sales would decline by more like 20%. Turns out it was 40%. To make matters worse, the price of precious metals shot up in part because of federal monetary policy trying to combat the recession (silver is a key component in photographic film).  Thus Kodak got squeezed on both sales and margins.

Along the way Kodak also grappled with the internal missteps that commonly plague struggling companies, most notably a loss of focus. The company explored the manufacture of chemicals, bathroom cleaners, and medical testing devices (among other things) in the ‘80s and ‘90s. And it even tried—too late as it turns out—to make a belated go of it in the digital camera business. Willy Shih, head of Kodak’s Consumer Digital unit in the 1990s, explained the hill the company had to climb. “With digital there is no film,” Shih said.  “You make your money by selling cameras. And you now needed to make components. You needed to make lenses; you needed to make shutters — all kinds of things that the skills for which no longer existed in Rochester.”

Over the past few years Kodak also succumbed to a loss of nerve, pursuing a strategy of IP licensing and lawsuits, then beginning to sell off its patents to generate needed cash. Alas, it was too little, too late.

The lesson? Technologies change. Competitors poach. Economies crater. And growth stalls. It happens to the best of companies (more than half in an average decade, according to our research). But what impacts your company from without is less significant than its impact within. As Fujifilm’s CEO Shigetaka Komori puts it, “As time passes, the fact shows that when a company loses its core business, some companies are able to adapt and overcome the situation, while others are not.”

Kodak made a fateful decision to not pursue digital imaging when it could have had the market to itself, and it failed to evolve quickly enough in a post-photographic-film world. That’s not to point a finger—nobody has perfect information, and all of us stumble.  It’s simply to say that while every company faces dramatic obstacles, addressing internal dynamics is as critical as responding to external events.

They say 40 is the new 30. When it comes to corporate growth, I sure hope so.

Management professors Charles Stubbart and Michael Knight completed a study of more than six million companies and found that only a fraction of them make it to their 40th birthdays.

In another study, economists Steven Davis and John Haltiwanger revealed that over a 28-year period (1977-2005), some 15% of jobs were destroyed each year, even as the net number of jobs in the U.S. grew by an average of 2% per year.

Those are two stunning statistics. As I explain in When Growth Stalls, our own research revealed that more than half of all companies stall over the course of an average decade–to say nothing of the past half-decade, which has been anything but average.

The lesson? We operate in a magnificent economy where competition and changing dynamics continually spawn new companies, new products and new services, weeding out weaker, less innovative offerings and enhancing everyone’s standard of living. That’s something to celebrate, not to mourn. The reason some jobs (and companies) go the way of the dinosaur is because more, newer and better ones arise to take their place.

No one can stop economic progress. The best we can do is recognize how it comes about and try to stay in front of the parade. As I intimated in a recent BusinessWeek.com column, as business leaders our task  is to ensure that we’re on the creative end of “creative destruction”, not the other (much less pleasant) one. If and as we do, everyone will be better off.

Sometimes the obvious needs stating: advertising works.

Oh, not just any advertising. Plenty of companies have been burned by bad strategy, bad execution, or bad execution of bad strategy. But most car wrecks are the fault of the driver. Here are just three examples of the incredible impact a well-thought, well-crafted campaign can have, from a retrospective on some of the more notable campaigns of last year.

Volkswagen debuted its “Darth Vader” commercial on the Super Bowl and the rest is history. 45 million YouTube views and $100 million in publicity later, the new Passat sold more in its first two months on the market than the previous model did in all of 2010.

Eminem made a surprise appearance in a Chrysler spot that was so captivating it’s “Imported from Detroit” tagline went viral and caused research on Chrysler’s website to jump 328%. More importantly, Chrysler sold 77,774 200′s during the first 11 months of 2011, three times the volume of the Sebring (its predecessor) in the same period a year earlier.

The big news this week is the appointment of Scott Thompson as the new CEO of Yahoo! News reports say his first priority is to lead a turnaround of the company’s online ad business.  They also say he’ll play “a big role” in the “ongoing strategic review” that the board is conducting. I would hope so.

But I have a question for Mr. Thompson: what, exactly, is Yahoo? I mean, Google is a search engine. Facebook is a social networking site. Twitter is a microblogging service. Yahoo is…a content company? What does that mean? If Thompson doesn’t have the answer—or at least a vision for getting to the answer—this is going to be nothing more than yet another seating arrangement on the Titanic.

Yahoo’s drift is evidence of a woeful lack of focus. That (arguably) may not be the fault of the board of directors, but telling the new guy to cut expenses and sell harder is not exactly a visionary charge, and more efficiently monetizing a depreciating asset is no recipe for growth. Thompson’s first published comments are somewhat contradictory, saying the company will “be back to innovation and disruptive concepts” (as if that narrowed things) while promising “if we don’t have it, we will find it in the market.” Ah yes, innovation by acquisition.

Yahoo is not a financial statement; it’s a business that got beat at its original game and has since suffered from a loss of identity and lack of vision. You might say it’s “pulling a Kodak”—and we know how that’s ending.

Yahoo either has a core competency and differentiating value proposition or it doesn’t, and one isn’t going to drop out of the clouds. If Thompson and the board can’t nail one down–and soon–they should call the game and give it up.