The Birth of a Nation might be the most well-known silent film not directed by Charlie Chaplin. It has everything you expect from a silent film of its era, with the actors employing a bold, expressionistic style and the scenes divided with "intertitles" (a fancy word for screens of text) that are used to describe the action and deliver speaking lines.
That being said, The Birth of a Nation invented many of these techniques—and then some. It was one of the first films to employ close-up shots. It was one of the first films to rapidly cut between scenes (think about the closing battle) in order to show that they're happening simultaneously. It even uses color tinting in certain scenes to give them a particular sort of emotional resonance.
So, yeah—it's pretty innovative. We might find the actual content of The Birth of a Nation to be revolting, but we can't deny that the film was an absolute game-changer when it comes to film production.