I started with Netflix in January. Soon after, I decided to put my queue in chronological order. Since then, I've rented 118 discs from them. Out of those, about 90 were made before 1930, meaning they were made before the techniques of adding sound to film were effective. I have finally finished watching all the silent films in my queue.
Watching such a silent film is like reading a book, in some ways. The viewer must use her imagination to understand what's going on beneath the surface. It takes more concentration, because you must watch the faces, the hands, the background, very closely. The actors use a type of pantomime to convey emotions. If necessary, the filmmaker will interrupt the action with an intertitle periodically, which is a blank screen with brief text on it, for dialog or a scene description, to help you along. Otherwise, all the action takes place on screen. Because they can't tell you much, they have to show you. This makes the films more active and visual. Netflix has hundreds of silent film titles. I recommend you start with The Thief of Bagdad (1924)