At 10:30 p.m. on 29 October 1969 (just a few months after Neil Armstrong had taken the first steps on the moon) a 21-year old UCLA student, named Charley Kline, took the phone, called the computer lab at Stanford, and under the supervision of UCLA computer science professor Leonard Kleinrock, managed to send the first message over an Internet connection.
At the other end was Bill Duvall, and they were working on the forerunner of the internet, called the ARPANET (Advanced Research Agency Network), an experimental network of four computers commissioned by the U.S. government and located at UCLA, Stanford Research Institute, UC Santa Barbara, and the University of Utah.
He tried to type in “LOGIN,” but the computers crashed after the first two letters.
Hence, the literal first message over the ARPANET was “lo”. About an hour later, having recovered from the crash, Kline was able to send the complete “Login” message.
The funny thing, though, is the very first message “LO” was prophetic.
(“Lo and behold!” is an expression used to present a new situation often with the suggestion that, though surprising, it could have been predicted.)