Academics at Universities really picked up on the net as way to communicate with colleagues world wide at time when long distance phone calls were very expensive.
Originally the net was tightly controlled by DOD.
In a historic quirk of fate, the the breakdown of the Soviet Union coincided almost perfectly with the development and mass marketing of powerful personal computers to consumers in the general public.
These users of these computers needed a way to link up and network with other users.
Researchers in the Silicone Valley were familiar with the ARPA net because many of them had worked on the development of the system or had been users of the system while in Grad School.
At universities like Stanford, the distinction between official and personal use of the net became blurred in the dynamic, free wheeling academic environment prevailing at the time as personal computer ownership by student and faculty soared and the DOD controls on the net wound down as the Cold War waned.
As a pioneer test case, Stanford University decided to wire the entire campus for networked communications from the dorms to the research labs and gave the project to a small Bay Area company run by a husband and wife team that developed and installed the hardware for the network using the ARPA net protocols as the framework for the system. The husband and wife did an amazing job of designing and building the hardware and even pulled the wire and installed the much of the system themselves. The system and the project was very successful and the husband and wife team went on to form a company known as Cisco Systems to commercialized the technology to the world market.
Stanford was a doable project because it already was extensively wired with infrastructure for the ARPA net, but the only existing infrastructure for a nation wide network was the DOD ARPA net.
At the same time the Cold War was winding down at an increasingly fast pace.
As the Cold War wound down, there were massive defense cuts so the military needs of the ARPA net declined and the DOD was looking for partners to share the enormous costs of keeping the network operating and maintaining it.
They looked to the emerging civilian computer networking industry to provide the necessary support.
Congress passed laws retooling the ARPA net for private use and the the rest is history. In fairness to AL Gore, he did take a lead in pushing this privatization.
You meant Silicon Valley. Silicone Valley is somewhere near Hollywood.
I've done extensive research in the Silicone Valley (see #73), but perhaps you meant the Silicon Valley?