In post-war America, folk songs and cowboy songs (also known, in those days, as hillbilly music) were beginning to be more popular with a wider audience. A subculture of rural jazz and blues fans had mixed elements of jazz and blues into traditional cowboy and folk song styles to produce a crossover called western swing. Thanks to the prevalence of radio, this music spread across the United States in the 1940s. Radio was the first "almost instantaneous" mass media with the power to create large subcultures by spreading the ideas of small subcultures across a wide area.