Email celebrates its 30th birthday

It was a short program - just 200 lines - but it was hooked up to the prototype of the internet, Arpanet.

Written by US engineer Ray Tomlinson, Cypnet allowed files to be sent to and from interconnected machines. There were more than a dozen machines on the internet in those days and spam, email viruses and HTML porn were not even invented.

Tomlinson then wrote a program to distinguish between messages addressed to the mailbox of a local machine, or those connected via Arpanet, with an @ keystroke.

He later said in an interview: "The @ symbol seemed to make sense. I used it to indicate that the user was 'at' some other host rather than being local." Most likely the first message was QWERTYIOP, or something similar, which is the top line of the keyboard.

And thus Tomlinson's new program became the first killer internet app. Two years later email represented 75 per cent of all traffic on Arpanet.

It took almost five years for the builders and designers of Arpanet to sit back and realise that, in many ways, email had become the real raison d'être for the new computer network.

But Cypnet was never a name that was going to catch on. It was not really until it became known as email, and the internet grew to the billions of sites we see today, that the app became as common in life as the telephone call.