Fun fact: graffiti was responsible for one of the earliest known memes. Kilroy Was Here became so popular with U.S. servicemen during World War II that it was rumored to be the code name of a spy. Nowadays, the internet may have done a pretty good job of taking over on the viral image front, but the artistry of graffiti has remained alive and well. The Facebook group "It's Graffiti, But Why?" is dedicated to proving this, with some of its most creative examples below.