At the time that OP is describing, censorship was very powerful indeed. Also, Allende's Chile cannot be easily compared to an Eastern Bloc nation in the '70s or '80s.

I could imagine some kind of network developed by an Eastern Bloc nation before 1990, but it would have been extremely centralized, hierarchical, and very strictly controlled.

> see China's rapidly developing communications infrastructure

Things have changed meanwhile, even in China.