Email is a method in the one you can Exchange messages for one or more recipients. To connect to the email you must need internet. For instant messaging the author and the recipient have to be connected at the same time.

An email consists of 3 parts:  

·         Message envelope

·         Message header

·         Message body

“Arpanet was becoming a human communication medium with very important advantages over normal U.S. mail and over telephone calls.” (Albert Vezza.)