The first message sent over that network, on Oct. 29, 1969, was just two letters: LO from the LOGIN that Charley Kline tried to type on a remote SDS 940 host system from his SDS Sigma 7 host computer via the brand new internetwork sponsored by the Advanced Research Projects Agency, also known as the Arpanet.
The problem that caused the crash was fixed later in the evening, but we're still left with the bizarre "LO" as the first message ever transmitted online. The Arpanet was a success and it laid the foundation for what would eventually become the internet.
