E-mail is one of the most common network applications in use today.
Although it might seem relatively new, e-mail was invented in the early 1970s.
Back then, of course, there was no Internet as we know it today, so having email
was a bit like owning a car before there was a highway system.
Today, e-mail is so widespread that ISPs just assume that you want an e-mail
address and automatically assign you one (or even several) when you begin
your service agreement.