Midnight in London. A long, shivering line of twentysomethings snakes outside a club in the West End. And most of them hold, as if an extension of their right hand, a mobile phone. Some are chatting with pals. Look closely, though, and you will see that many others are text messaging their friends, checking up on who's making out with whom, which clubs are hot tonight; constantly punching the numeric keypad as if to prove that the opposable thumb is what distinguishes humans from lesser primates.
In Europe and Japan, mobile phones have become the indispensable tool of youth. At...