Godwin's law (or Godwin's rule of Nazi analogies)[1][2] is an Internet adage asserting that "As an online discussion grows longer, the probability of a comparison involving Nazis or Hitler approaches 1"[2][3]—​that is, if an online discussion (regardless of topic or scope) goes on long enough, sooner or later someone will compare someone or something to Hitler or Nazism. -- Widipedia