Spend any time on the Shanghai metro and you'll be impressed not just by its efficiency and cleanliness, but also by the number of thumbs racing over mobile phones, sending text messages to friends. While texting has yet to take off in the United States, where the low price of local calls makes it easy to just dial and talk, in China, SMS messages are all the rage.

(And if you're wondering how people send text messages in a country with no alphabet and more than 50,000 characters, it's actually easier - and faster - than you might think. Subscribers write in pinyin, a Romanization of Chinese, and then choose the character they want from a list. It's fast and accurate.)

But it's not just messaging that makes China's mobile phone subscribers happy. Mobile users in the People's Republic are also enthusiastic down loaders of color ring-back tones, tunes that play while the dialer is waiting for the call recipient to answer. General ringtones are popular too, giving cell phone providers and Internet sites plenty of reasons to smile.

In fact, China Mobile's color ring-back tones and other services gave it revenues of 6.99 billion Yuan (US$872 million) last year, more than 2.5 times the amount generated the year before. It's not surprising then that Chinese Internet companies too are scrambling to load up on tunes for users to download.

Although China's population is well over a billion, much of the country's new prosperity is on the east coast. Mobile phone use however, is popular everywhere. China has a relatively low rate of mobile phone use on a per capita basis but by virtue of a population exceeding 1.29 billion it is reviewed as the world's number two mobile phones market, only second to the US with more than 75 million subscribers.