Technology breeds agile thumbs. The trend is most notable among Japan's young "oya yubi sedai" or "the thumb generation." Ninety-seven percent of all Japanese college students have cellphones; 79 percent of high-schoolers do. And while infrequent cellphone users tend to hold the phone in one hand and tap it with the other, Japan's mobile masters clasp the phone in one hand and press the keypad with their thumb. Sending text messages using kanji characters requires special dexterity, and such messages are very popular. Young Japanese consider it rude to call without "texting" first. Observers note that the "ketai" (cellphone) kids are using their thumbs more often to point at things and to ring doorbells.
Sources: 'On the Mobile: The Effects of Mobile Telephones on Social and Individual Life,' a study by Sadie Plant; 'Beyond the Net,' by Janine Warner, Miami Herald for April 7, 2003.