Consumer preferences may change rapidly. It seems that these preferences change almost without warning. When they change, the nature of the market changes. Old products are now boring. Companies have to adjust. Perhaps they scrap old products and offer new ones. Maybe they modify an old product. The underlying strategic issue is to see these changes in the environment and react to them.

Michael Porter has written several books on this subject (he is a good resource). He uses the expression "competitive advantage" to indicate how some organizations can catch the wave of change and out-perform their competitors.

Can you identify two examples of this kind of change? Take a well-known historic example: beer. Consumers developed a preference for "light" beer and now light beer controls a good deal of the market, replacing "heavy" beer. What others can you think of?