Electronic mail, commonly known as
email or
e-mail, is a method of exchanging digital messages from an author to one or more recipients. Modern email operates across the
Internet or other
computer networks. Some early email systems required that the author and the recipient both be
online at the same time, in common with
instant messaging. Today's email systems are based on a
store-and-forward model. Email
servers accept, forward, deliver and store messages. Neither the users nor their computers are required to be online simultaneously; they need connect only briefly, typically to an
email server, for as long as it takes to send or receive messages.