If we leave out social impacts, the main impacts on the US were economic and political.
Politically, World War I helped to cause a certain amount of intolerance in the US. It was during this war that the Espionage and Sedition Acts were passed. These laws made it essentially illegal to criticize the government or the war. The war also helped to lead to the Red Scare and crackdown against political radicals that occurred right after the war.
Economically, the war helped move the US more towards a system in which the government and businesses cooperated with one another. The government had to coordinate with businesses in order to get businesses to make a quick switch from peacetime production to war production. This caused a great deal more interconnection between business and government than had previously existed.