The Economist recently ran an interesting piece that is based on the just-released World Bank Global Economic Prospects report.

A key passage:

But the degree varies widely. In almost all industrialised countries, once a technology is adopted it goes on to achieve mass-market scale, reaching 25% of the market for that particular device. Usually it hits 50%. In the World Bank’s (admittedly incomplete) database, there are 28 examples of a new technology reaching 5% of the market in a rich country; of those, 23 went on to achieve over 50%. In other words, if something gets a foothold in a rich country, it usually spreads widely.

In emerging markets this is not necessarily so. The bank has 67 examples of a technology reaching 5% of the market in developing countries—but only six went on to capture half the national market. Where it did catch on, it usually spread as quickly as in the West. But the more striking finding is that the spread was so rare. Developing countries have been good at getting access to technology—and much less good at putting it to widespread use.

As a result, technology use in developing countries is highly concentrated.