Whenever we have thanked these men and women for what they have done for us, without exception they have expressed gratitude for having the chance to help - because they grew as they served.

By the time it becomes obvious that a technology will have truly disruptive impact, it is often too late to take action. This is one reason why we are such advocates of using theory to try to analyze industry change. Conclusive evidence that proves that a company needs to take action almost never exists. In fact, the data can fool management, lulling them into a false sense of security.

If you just look at the data, you are led to believe that things are getting better, rather than worse. That's why the fall is really precipitous, once you hit the ceiling.

Ultimately, when you come up with a classification scheme that is collectively exhaustive and mutually exclusive, then the theory can become what Kuhn called a paradigm.

There needs to be conviction and action behind rules.

How could Digital's collapse be so precipitous? It's because, in many ways, financial performance data is misleading. As you move up to the top of the market, you're getting rid of the less profitable products at the low end and adding business with more attractive margins at the high end. The rate of unit volume growth might be tapering off as you pursue these smaller markets, but your margins actually look better. So Wall Street rewards your stock price until you hit the ceiling.

One of the factors that make great companies so great is that they have processes that allow them to solve difficult problems again and again. These processes have developed over time as teams have successfully wrestled with a certain type of challenge. Eventually, people begin to say, "This is just how we do something around here." The problem develops when that team then has to solve a very different set of challenges. The processes that are such strengths can be crushing liabilities.