Electronic Mail

    The next big thing to come was when Len Kleinrock invented electronic mail or email in 1973 even though the ARPANET was not intended to be a message system (When Wizards Stay Up Late). Email is a way to send  messages that can contain text only, or it may contain text with pictures, sound clips, moving pictures or videos ( World Book).
Picture
The Picture to the left shows how email works.
Picture from Wikipedia .org 
This is a youtube video of how email works. Video by WydeaWonders.