During World War I, the impact of the poster as a means of communication was greater than at any other time during history. The ability of posters to inspire, inform, and persuade combined with vibrant design trends in many of the participating countries to produce thousands of interesting visual works. As a valuable historical research resource, the posters provide multiple points of view for understanding this global conflict. As artistic works, the posters range in style from graphically vibrant works by well-known designers to anonymous broadsides (predominantly text). Countries on both sides of the conflict distributed posters widely to garner support, urge action, and boost morale. Even with its late entry into the war, the United States produced more posters than any other country. Taken as a whole, the imagery in American posters is more positive than the relatively somber appearance of the German posters.
During World War II, a larger quantity of posters were printed, but they were no longer the primary source of information. By that time, posters shared their audience with radio and film.