"One college student I spoke to described leaving one's phone at home or letting the battery die as "the new taboo." Teens and twentysomethings usually do not bother to set a time and place for their meetings. They exchange as many as 5 to 15 messages throughout the day that progressively narrows in on a time and place, two points eventually converging in a coordinated dance through the urban jungle. To not have a keitai is to be walking blind, disconnected from just-in-time information on where and when you are in the social networks of time and place."
Japan Media Review: A New Set of Social Rules for a Newly Wireless Society