I am positive that the first message send between the computers was something adorable like this.

Transcript:

A banner day in geek history! Also mash-notes history! Mr Bugg stands at a computer terminal typing out an important message: “I like U!”. His computer is connected by a cable to Mrs Bugg’s computer, which is depicted as right next to Mr Bugg’s, by way of artistic license, but which was in reality a couple hundred miles up the coast. Mrs Bugg is smiling and blushing; we can’t see her monitor but it’s a good bet that she’s gotten Mr Bugg’s message.

The text reads: “Bugvember 21, 1969: The first BARPANET link is established between BuggCLA and SRI.”