The first message sent over the internet was the word LOGIN, but the system crashed after the first two letters.
Why it is true
On October 29, 1969, a student attempted to send the word LOGIN from a computer at UCLA to another at the Stanford Research Institute. The system successfully transmitted the letters L and O, but crashed before completing the word. The first actual message on the internet was therefore just LO.
Source: MIT
Would you rather be asked first?
This is the reading side of the site, so the answer is in the sentence above — that is the whole point of it. Test yourself works the other way round: the question comes on its own, and the fact and the explanation only appear once you have answered.