Ray Tomlinson created one of the biggest communications phenomena almost by accident - e-mail.
In 1971 he was tinkering with a programme that allowed staff at ARPANET to leave messages for each other. He'd been working on an experimental computer program called CYPNET that transferred files between linked computers, and thought it would be a neat idea if you could transfer messages as well as files.
He chose the "@" symbol to mark the difference between a message that needed to go to a mailbox on the local computer and one that was headed out onto the network.
Typically, he told his colleagues about it via the mail system and it caught on like wildfire - although it took about five years before ARPANET realised what a hot property they had.
Tomlinson continues to work in software to this day.