You can read the 2400 word essay I posted yesterday about D.W. Griffith's development of a film "language" and how he taught every director from Charlie Chaplin to Christopher Nolan how to manipulate an audience's emotions, or you can watch this 49-second clip from 30 Rock, which pretty much covers the same territory. Your call.
(You can watch the entire episode here at Hulu.)
Silent Movie Trivia #13: The Wizard of Oz (1925)
18 minutes ago