During World War I the British produced a recruitment poster depicting a pointing Lord Kitchener, the British Secretary of State for War, above the words "WANTS YOU."  This poster would serve as the most famous of all the British recruitment posters during the war.

Three years later, the united states mimicked the poster with Uncle Sam declaring "I WANT YOU FOR U.S. ARMY."  The United States version was the first of many imitations of the Lord Kitchener's famous poster.  The imitations range from a German version of the poster printed in 1919, to several Russian recruitment posters dating from 1920 to 1941, to it's most recent popularized rendition pictured below.

Wikipedia

[Source: Wikipedia]