Current projections about developing world use of the Internet generally feature a linear growth pattern. That is a rational way of think about it.
But it also is likely to be wrong. Forecasters looking at use of voice communications in the developing world likewise were linear.
But those forecasts were quite wrong. Why they were wrong is a story about deregulation, competition, using "capital-rational" networks and changing consumer perception of value.
Voice communications, provided by mobile networks, became non-linear and exponential over a brief period of not even a decade.
Based on that precedent, one also would predict that Internet adoption in the developed world also will be non-linear. It is hard to predict, as the impact of mobile communications was hard to predict.
But one clear implication is that the massive adoption wave happened only when service providers switched from expensive fixed networks to more-affordable wireless networks. In fact, from 1997 to 2007, world fixed lines were up relatively slightly.
As with voice, mobility and wireless are likely to be the foundations for a similar upsurge of Internet access in developing nations.