I'm the thinking primarily of cultural exports in the form of film, television and other mass media. Presumably America's success at exporting its culture is due to the simultaneous development of mass communication and the apogee of American world power. To what extent are there precedents prior to the 20th century in terms of nations that achieved similar success in exporting their culture?
Well, there is England, which exported its language to the United States, Canada, Australia, New Zealand, South Africa, and many other places, exported its style of clothing (particularly men's clothing) to most of the world, and exported many other cultural elements as well.