I remember seeing that - I got online in late 1978, at Columbia University. Somewhere in my files is a slightly later map, printed on greenbar lineprinter paper, of the ARPANet circa '79 - about 200 hosts.
Back then, Mail, Telnet, and FTP were the killer apps, and the large mailing list (the first online social media) got started with SF-Lovers, albeit sub-rosa.
Back then, everyone online either worked for a government contractor, or was at a university which contracted to the government. The level of helpfulness and collegiality was far, far higher than today.