There are as many mobile handsets on a Japanese commuter train as on the commuter trains of any other rich economy. Yet in Japan, the telephones are curiously silent. Instead of speaking into sleek silver gadgets, users are busy sending e-mails or downloading pictures of their favourite pop stars.

Japan's growing band of e-mail junkies has driven the phenomenal success of NTT DoCoMo's i-mode, the mobile phone service which offers continuous internet access. According to DoCoMo, the largest mobile phone operator in Japan, by April, its mobile internet service boasted 22m subscribers - almost one in six Japanese.

European operators look on with envy - and desperation. Europe's wireless application protocol (Wap) internet phones have failed to make an impact. Meanwhile, operators have spent billions acquiring third generation (3G) mobile licences to support even more advanced services. The more European telecom shares are hit by scepticism about Wap and worries about the debt taken on to pay for new investment, the more European operators turn to Japan for inspiration and hope.

Hence the importance of understanding the reasons for i-mode's success - and the worrying possibility that western excitement about wireless internet services may be based on several i-mode myths.

To begin with, in the west there is a widespread misperception that the wireless internet is all about technology. One view is that once i-mode-style packet switching replaces the circuit switching of traditional telephony, the demand for wireless internet services should take off. With packet switching, the telephone can be continuously connected to various websites. It also lowers the cost of sending data.

I-mode does have technical advantages. For one thing it uses a variant of HTML, the standard script of the internet, unlike Wap which runs on a completely different language. In addition, packet switching saves users the hassle of calling up a website every time they need to interact with one.

But packet switching is not everything. J-Phone, a smaller competitor to DoCoMo, has been able to amass 3m subscribers to its J-Sky internet service even though it uses circuit-switched technology.

Another common European view is that the faster access speeds of 3G networks will finally make possible the wireless internet revolution. But at 9.6 kilobits per second, i-mode's data transmission rate can hardly be described as fast. Moreover, to the extent that speed matters, the news from Japan about third-generation telephony is bad.

Japan will be the first to launch 3G, and DoCoMo has tested equipment provided by NEC in a full-scale trial in southern Japan. Recently, however, DoCoMo sent shivers through the industry when it revealed that only when used by a few users at a time does w-CDMA do everything its designers promise. The limits of available radio spectrum mean that the standard can't simultaneously provide the very high data speeds needed for video and sound transmission to large numbers of users over long periods.

In densely populated cities, it would be more practical to download short, 10- or 15-second clips of music and video. If customers like what they see, they can order a full-length recording of a pop song or sports event to enjoy at home downloaded over fixed telecommunications networks. That is one reason why DoCoMo was keen to tie up with America Online in developing services that combine the benefits of both fixed and mobile internet access.

Japanese operators are wary of technology for technology's sake. "Wap failed [in Europe] because operators concentrated too much on the technology rather than the content," says Keiichi Enoki, leader of the i-mode project team. "It is like worrying about the quality of television sets before you have any programmes."

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