Ray Tomlinson, 1972
Computer engineer Ray Tomlinson worked for Bolt Beranek and Newman (BBN) as an ARPAnet contractor. ARPAnet – the forerunner of today’s Internet – made a large contribution to the development of electronic mail. Though e-mail is actually much older than ARPAnet, Tomlinson is credited for implementing the first Internet based e-mail system in 1971. He picked the @ sign to denote sending messages from one computer to another, which has been used in e-mail addresses ever since. Statistics in 2010 estimated the number of e-mails sent per day to be around 294 billion.