More generally, in the realm of physical production, where scarce resources are critical inputs, each additional unit of output is usually more costly to produce than the previous one; that is, production, at least eventually, is characterized by increasing marginal cost. By contrast, in the realm of conceptual output, much of production is characterized by constant, and perhaps even zero, marginal cost.
For example, though the set-up cost of creating an on-line encyclopedia may be enormous, the cost of reproduction and distribution may be near zero if the means of distribution is the Internet. The emergence of an electronic platform for the transmission of ideas at negligible marginal cost may, therefore, be an important factor explaining the recent increased conceptualization of the GDP.