Emerging Business Applications in the Japanese Mobile Internet by Professor Jeffrey L. Funk, author of Mobile Disruption.

It is ironic that there are probably many more mobile Internet business users in Japan than in the United States or Europe in spite of the fact that U.S. and European service providers initially placed much more emphasis on business users than Japanese service providers (e.g., see J.P. Morgan, 2000).

The reason for this unexpected turn of events is that screen savers and ring tones -- and the micro-payment services that support these contents -- created a critical mass of users in Japan, which in turn has driven innovation in the market. Improvements in displays, camera phones, application processors, memory and software are improving the performance-cost ratios of business applications (Funk, 2001; Funk, 2003).

See also:
Disruption! How the Mobile Phone is Changing the Japanese Internet and Software Industries (PDF)