I was at a meeting today, and I heard someone yet again talking about killer apps for mobile telephones. Killer apps are, apart from a horrible name, applications that are so compelling, people buy the hardware just in order to be able to run them. But mobile phones don't need a killer app; people are buying them in huge numbers anyway. Why? Because mobile phones are their own killer app, because they already have the compelling functionality that people want: to communicate with other people.
There are some people who thought that WAP would be a killer app for mobile phones. WAP is the World Wide Web in every detail, using the same protocols, with one difference: It uses another markup language, WML, instead of HTML. This was a stupid choice for several reasons: 1) Metcalf's law, 2) Lessons of leverage, 3) The single telephone effect. Proponents may have thought that because mobile telephones have small screens and little memory, they had little chance of being able to process HTML. On the other hand these people may have thought they could corner a section of the market. They were wrong.
Metcalf's law states that a network's value is the square of the number of nodes. Double the number of nodes, the network is worth four times as much; halve the number of nodes, the network is worth a quarter. So trying to create a separate WAP network divides the space into two smaller networks rather than one big one, reducing the total value.
When Tim Berners-Lee and Robert Cailliau first created the Web, they did a clever thing: they included existing network protocols as a part of the Web. At that time, people who supplied information over the Internet did so largely via FTP. When the Web came along, you could tie your FTP data together in no time with a Web page, immediately creating Web content almost for free. Leverage. The WAP designers didn't learn this lesson, so the WAP web had to be created from scratch.
It's no fun being the only person in the world with a telephone (actually this is just Metcalf's law expressed in a different way). If no one has a WAP phone, there's little reason to provide WAP content; if there's no WAP content, there's no reason to buy a WAP phone. That's why you need leverage to get your initial content off the ground.
So it's no wonder that WAP hasn't taken off (even if you ignore the slow response times with the meter ticking).
And then look at i-mode in Japan. Almost exactly the same as WAP, but a huge success. Why? I think there are three reasons: they used a variant of HTMLyou can access the Web from your phone (it is a great experience to sit with a colleague in a restaurant in Japan, and ask what sort of fish a particular dish is, and see him go to a dictionary site on the Web and look it up); it is always onthere are no connect times involved; it was designed by a woman. People seem to have missed an extraordinary property of mobile phones: it is technology loved as much by women as by men (for different reasons of course). This struck me with a force travelling around in Tokyo: women everywhere staring at the screens of their mobile phones with equal enthusiasm as men. I-mode seems to have realized this, and done as much to address women, the design of the phones, the design of the content, as for men.
©2001 ACM 1072-5220/01/0700 $5.00
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