Propaganda posters during World War 1 and World War 2 extensively in Europe, Australia, New Zealand, The USA, The United Kingdom and even in Germany. They were used to motivate people to buy war bonds to support both wars. They were also informational and educational. Mostly though they were motivational. They encouraged people to cooperate with rationing, conscription, to write to the service men and women, to plant victory gardens and to use the bomb shelters. You can see the posters on many web sites.