Obviously, wars are fought on the battlefield, but what impact did WWI have on the home front?
World War I had different impacts on different home fronts. The Belgians, for example, were overrun and atrocities committed against them. The French had the war happen on their soil and Paris was shelled by long range artillery. Air ships dropped bombs on England more than 100 times. These countries, along with Germany, also had to mobilize their entire societies to participate in the war effort.
In this answer, however, I will concentrate on the impact the war had on the United States. I will look at the war from an economic point of view and from a social/political point of view.
Economically, the onset of the war forced the US government to try to coordinate more closely with industry. World War I can be seen as the first truly industrial war and the US had to make sure that its industry got fully behind the war effort. The government worked closely with industry and agriculture to ensure that the goods that were needed for the war would be produced. This was a new thing in the US as the government had typically been more “hands-off.”
Socially and politically, the war had a tremendous impact. The government decided that it needed to bolster public opinion in favor of the war effort and against Germany. This led to the creation of a concerted propaganda effort. It also led to the Espionage and Sedition Acts, which essentially banned criticism of the government and/or the war. These actions led to the erosion of civil liberties and to widespread animosity against Germans and people who did not support the war.