Film trailers are an important part of marketing a film. They are shorter versions of the film designed to introduce audiences to the genre and plot. Trailers are shown in theaters, on television, and online to generate excitement for a film's release. Effective trailers appeal to target audiences and communicate a film's unique selling point to encourage people to see the film. They must be released far enough before a film's release to build interest but not so early that audiences forget about it by the time it is released.