We lost Ray Tomlinson on this day in 2016; known as the inventor of email,
he sent the first message between two hosts on the ARPAnet (prior to that
the users had to be on the same host), and pioneered the use of the "@"
sign.
In the meantime, some tosser (his name is not important) is claiming that
he invented email first; I recall that APL\360 had a "mailbox" facility,
but it certainly didn't use "@".
--
Dave Horsfall DTM (VK2KFU) "Those who don't understand security will
suffer."