When the Soviet Union launched Sputnik, beating American in some of the early first steps of the space race, American created an agency known as the Advanced Research Projects Agency (ARPA). They hoped to demonstrate their techonolgical skill to both the Soviets and the rest of the world. One of the early projcets of ARPA was the ARPANET. ARPANET was the worlds first packet switching network.
There were four computers on ARPANET. One each at UCLA, Stanford, UC Santa Barbara, and the University of Utah. At 10:30 PM on October 29, 1969, a message was sent from the computer at UCLA to the one at Stanford. The message was supposed to be the word "login." The "l" and the "o" transmitted without problem but then the system crashed. Hence, the first message on the ARPANET was "lo".