Word-of-mouth communication

My son, a junior high school student, has started using e-mails by mobile phone. No one in my family taught him how to use it. His friends might be the same. They might be taught by their elder brothers and sisters. Besides mobile phones, TV games,
PCs, i-pods, i-phones and other electronic gadgets has become popular. Manual? No need. Word-of-mouth communication is the most important and valuable way of information communication.
Kan-ami transferred the secrets of Noh farce to his son, Ze-ami, by word-of mouth in the 15th century.Ze-ami wrote a famous art book of "Fushikaden", but this contents had been secret for a long time, as "Hisureba hana nari, hisezuha hana narubekarazu" ( if secret, it will become a flower, if not secret, it will not become a flower ). The real "flower" is created by heart innovation.