Good writeup. Communication is faster nowadays. Mobile phone helps the owners learn how to write their messages and send by themselves. In those days when people communicated via letter writing there was no privacy for most people. They invited few literate persons to do it for them. Same thing happened when they received letters. People had to treck or take vehicles to be able to go to the post office or places they can telegraph such as big post offices and railway station. Phone has tremendously changed the way people do things. May I state that you forgot that phones can be used to hold meetings, conferences and lectures. Students do research on phone. Thank you for your write up.