Read this excerpt from "why no policeman on the block? "

only in the last decade, with the ending of the cold war, have these technologies finally been fully released to the public domain.

what is the meaning of the underlined term?
civilian researchers
open society
mass media
unlicensed users

The answer to the question above is "open society" is the meaning of the underlined term assuming that "public domain" is the underlined term. The meaning of "public" word as an adjective is "exists in an open view" and the meaning of "domain" word is "an area controlled by a government. These meanings also included in the "open society" term.