*He achieved what no other known man has ever achieved. To watch his work is like being witness to the beginning of melody, or the first conscious use of the lever or the wheel; the emergence, coordination, and first eloquence of language; thebirth of an art: and to realize that this is all the work of one man. - James Agee *

Griffith demonstrated to every filmmaker and moviegoer who followed him what a movie was, and what a movie could be. - Roger Ebert

I believe directing a movie is consciously combining the art of using the camera and the techniques, the music or anything to achieve the vision or idea you have in your mind to make use of these tools to create something impossible and before Griffith - maybe all the inventions were there but with no vision of this kind! Inventions become obsolete, but not visions or ideas!

Several filming innovations belong solely to Griffith (some of which he invented during his collaboration with G.W. Bitzer at The Biograph Co. They include the flashback, the iris shot, the mask, the systematic use of the soft focus shot and the split screen. Griffith pioneered the technique of parallel editing, which he used extensively after 1909. He invented false eyelashes in 1916 for Intolerance: Love's Struggle Throughout the Ages (1916). He was the first to utter the catchphrase "Lights, camera, action!" in 1910, on the set of In Old California (1910). It, like many of his techniques, are still widely used in filmmaking.

Hence, he has been called "the father of film technique," "the man who invented Hollywood," and "the Shakespeare of the screen"

Again, Roger Ebert in his great movies collection has discovered a lot more than typical audience, critics has found:

"Today, what they saw for the first time, we cannot see at all. Griffith assembled and perfected the early discoveries of film language, and his cinematic techniques that have influenced the visual strategies of virtually every film made since; they have become so familiar we are not even aware of them.. ". " One of Griffith's key contributions was his pioneering use of cross-cutting to follow parallel lines of action." "Griffith uses elevated shots to provide a high-angle view of the battlefields, and cuts between parallel actions to make the battles comprehensible; they are not simply big tableaux of action." "He was the first director to understand instinctively how a movie could mimic the human ability to scan an event quickly, noting details in the midst of the larger picture. Many silent films moved slowly, as if afraid to get ahead of their audiences; Griffith springs forward eagerly, and the impact on his audiences was unprecedented; they were learning for the first time what a movie was capable of."

Again to quote James Agee

"... The frame was always full, spontaneous, and lively. He knew wonderfully well how to contrast and combine different intensities throughout an immense range of emotion, movement, shadow, and light.... " " His last movie, which was never even released, was made fourteen or fifteen years ago; and for years before that, most people had thought of him as a has-been. Nobody would hire him; he had nothing to do. He lived too long, and that is one of few things that are sadder than dying too soon. There is not a man working in movies, or a man who cares for them, who does not owe Griffith more than he owes anybody else."

Sources: Encyclopedia Britannica; The Nation; RogerEbert.com; The Internet Movie Database.