Some readers might still remember the website "An Atlas of Cyberspaces" at cybergeography.org, now unfortunately only available as a static online archive. Back in the days, it was a very inspirational site that collected various "information maps" that explored the realm of graphical representations of "cyberspace", and of Internet networks in particular.
Anyway, connected to this website was a book that originally appeared in 2002. Its contents are now freely available as a series of high resolution (228MB) PDF sections available here. The book gives an interesting overview of the early years of (more "popular" forms of) data visualization, including chapters about mapping Internet infrastructure and traffic flows, mapping the Web, mapping online conversation and community, imagining cyberspace in art, literature, and film. It comes highly recommended.