In 1973, New York listener-supported radio station, WBAI-FM (owned by the Pacifica Foundation), aired Carlin's routine which brought a complaint from a father whose son had heard the broadcast. The Federal Communications Commission was notified, an investigation ensued, and eventually WBAI-FM was fined for broadcasting obscene content. WBAI-FM appealed the ruling and it eventually went to the highest court in the United States.
Five years later, by a 5-4 vote, the Supreme Court upheld the F.C.C. decision ruling the routine was "indecent but not obscene".
FCC v. Pacifica Foundation is one of the highest profile free speech cases of the last century and it served to make George Carlin a household word and also helped define Radio's verbal boundaries for the future.
Related: Offensive Speech vs. Free Speech
View: Watch George Carlin perform "Seven Words You Can Never Perform on Television" (Warning: offensive language)