MANKIND'S progress in developing new gizmos is often referred to as the 'march of technology'. That conjures up images of constant and relentless forward movement orchestrated with military precision. In reality, technological progress is rather less orderly. Some technologies do indeed improve at such a predictable pace that they obey simple formulae such as Moore's law, which acts as a battle plan for the semiconductor industry. Other technologies proceed by painful lurches—think of third-generation mobile phones, or new versions of Microsoft Windows. There are even the occasional backward steps: you can skip over the trailers when watching a film on video, but for some reason you are not allowed to do so when watching a DVD. And there are some cases, particularly in the developing world, when technological progress takes the form. of a leapfrog. Such leapfrogging involves adopting a new technology directly, and skipping over the earlier, inferior versions of it that came before. By far the best-known example is that of mobile phones in the developing world. Fixed-line networks are poor or non-existent in many developing countries, so people have leapfrogged straight to mobile phones instead. The number of mobile phones now far outstrips the number of fixed-line telephones in China, India and sub-Saharan Africa. By their very nature, mobile networks are far easier, faster and cheaper to deploy than fixed-line networks. There are other examples. Incandescent light bulbs, introduced in the late 1870s, are slowly being displaced in the developed world by more energy-efficient light-emitting diodes (LEDs), in applications from traffic lights to domestic lighting. LEDs could, however, have an even greater impact in parts of the developing world that lack mains power and electric lighting altogether. LEDs' greater energy efficiency makes it possible to run them from batteries charged by solar panels during the day. So there is the prospect of another leapfrog, as the rural poor skip over centralised electric grids and straight to a world of energy-efficient appliances run using local 'micropower' energy sources. Other leapfrogs include the embrace by China and Brazil of open source software, and China's plan to build a series of 'eco-cities' from scratch based on new green technologies. Being behind the 'bleeding edge' of technological development can sometimes be a good thing, in short. It means that early versions of a technology, which may be buggy, unreliable or otherwise inferior, can be avoided. America, for example, was the first country to adopt colour television, which explains why American television still looks so bad today: other countries came to the technology later and adopted technically superior standards. Leapfrog technologies can also spread faster, because they do not face competition from entrenched earlier systems. And leapfrogging straight to a green technology means there is no need to dispose of the old, dirty one. By the time Chinese consumers started buying fridges in large numbers, for example, refrigeration technology no longer depended on ozone-destroying CFCs. The lesson to be drawn from all of this is that it is wrong to assume that developing countries will follow the same technological course as developed nations. Having skipped fixed-line telephones, some parts of the world may well skip desktop computers in favour of portable devices, for example. Entire economies may even leapfrog from agriculture straight to high-tech industries. That is what happened in Israel, which went from citrus farming to microchips India, similarly, is doing its best to jump straight to a high-tech service economy. Rwanda even hopes to turn itself into an African tech hub. Those who anticipate and facilitate leapfrogging can prosper as a result. Those who fail to see it coming risk being jumped over. Kodak, for example, hit by the sudden rise of digital cameras in the