The document discusses the different types and purposes of movie trailers. It explains that there are usually two main types of trailers released - a short teaser trailer and a longer theatrical trailer. Trailers are shown in theaters, online, and on television to generate buzz and anticipation for upcoming films. They aim to indicate the genre, story, and starring actors to appeal to target audiences and encourage viewers to watch the film. Trailers highlight exciting elements and establish a film's unique selling point to distinguish it from other similar movies.