Markets as difference engines:

From an article today by Phil Patton in the NYT:

The Japanese succeeded in the United States in the 70’s partly by reducing the number of options, and American makers followed suit. Choices shrank. It was left to small companies to offer optional equipment.

Personalizing vehicles has inspired the growth of a vast array of small companies offering parts, wheels, engine parts, audio equipment and so on. The market for auto accessories grew from $4.35 billion in 1990 to $8.69 billion in 2000, according to the Speciality Equipment Market Association, or SEMA, a trade organization.

References

Patton, Phil. Dad to Virtual Rad? New York Times. October 27, 2004.