When the World Wide Web launched in 1993, it seemed to catch on and spread overnight, unlike most new technologies, which typically take at least a decade to move from first "proof of concept" to broad acceptance. But the Web did not really emerge in a single year. It built on infrastructure, including the construction of the Internet between 1965 and 1993, as well as a sudden recognition that resources, such as personal computers, had passed a critical threshold.

Vision and market forces also push the development and spread of new technologies. The space program, for example, started with a government vision, and only much later did military and civilian uses for satellites propel the industry to commercial viability. Looking forward to the next technological revolution, which may be in biotechnology, one can begin to imagine what markets, visions, discoveries and inventions may shape its outcome and what critical thresholds in infrastructure and resources will make it possible....