Hi there, so as per the title, I'm wondering if there were any of those "dude this thing, the internet, it's gonna change everything, you'll be able to do this, that, blah blah blah" people out there?
I'd certainly recommend waiting for a more-versed expert, but my impression is that Marshall Macluhan, the Canadian media theorist, fits the bill here for his work on mass media communication in the 1960s when he saw electronic communication revolution looming.
He foresaw a 'global village' based on the breakdown of individualism following electronic media normalization, as written in The Gutenburg Galaxy in 1962. He put fingers in many pies, from early celebrity culture to his influence on critical theorists like Boudrilliard, and I certainly can't do justice here and now as to which ideas found a hold and why. Here are a couple passages to illustrate his bombastic style:
"The new electronic interdependence recreates the world in the image of a global village.“
The following can be seen as prelude to Macluhan's ideas on hot and warm medias, which did not catch on, and cybernetics, which did:
"When technology extends one of our senses, a new translation of culture occurs as swiftly as the new technology is interiorized."
A common critique of Macluhan's more famous The Medium is the Massage as seen in Sandywell's 2013 review is that Macluhan's work is often chaotic, provocative, and even absurdist. I don't believe its a liberty to say that he must have appeared a bombastic doomsayer, as many early postmodernists must have looked to the modernist lens of the time. As many cybercultural shifts happened a decade or more after his seminal works, and by other prominent writers too, it can be hard to determine exactly which truth statements Macluhan made that weren't tied up in predictions which also failed to come true. In short, Macluhan was early to the electronic age and radical enough to announce it, but also overstepped on other predictions.
This is but a start to an answer to this question, and I feel confident that Macluhan and his contemporaries were grasping internet-like possibilities in the late 50's if the last quarter of his 1962 book already proclaimed the beginning of the typographical and electronic age of society.