The first message was sent from one computer to another over ARPANET on October 29th at 22:30. ‘LO’ for Login, but then the computer crashed as Charley S Kline typed the G. Famous first words. Leonard Kleinrock describes the events that led to that first internet message in a blogpost.
I was born some 6 months after that first transmission, and first went online in november 1989, almost exactly 20 years after ‘LO’ chirped over the wires between computers.
Below is a photo of the logbook with the entry of the first internet message. And a cut-out of the message itself. Oddly enough there’s no freely re-usable photo of this historic document out there. Wikimedia has an image, which is only public domain in the USA, but still copyrighted everywhere else. The image below is by Andrew “FastLizard4” Adams, who took the photo 29 October 2011, the 42nd anniversary of the message when the Kleinrock Internet Heritage site was opened in Boelter Hall 3420 at UCLA, the room where it happened. He released it under a CC BY SA license, which therefore is also the license attached to the cut-out I made from it. Someone really should visit that place to take a picture and put it in the public domain or under CC0 globally (although the CC BY SA license of the image below is an acceptable one for Wikimedia too).