Small film scenes advertised for promoting new films and are not yet released are called film trailers. They are short description of the movie which explains what the film is all about and its story line and introduce the actors and the scenery.
These short clips of the upcoming movies are called film trailers because in early years of cinema, the advertisements for one film were shown after another film. Now the trends have changed and the movie trailers are shown at the start of the movie such that people do not miss them.

Normally the best and the most exciting scenes of the film are selected as the trailer of that particular movie. Sometimes special shot scenes are used as film trailers and used only for the promotion purpose and is not shown in the original movie when it is out in cinemas. For example, in a trailer for the classic Casablanca, the character Rick Blaine says, ?OK, you asked for it!? Before he shoots Major Strasser, a scene not present in the final film.

Normally trailers start with a green or red band graphic at the beginning which indicates its certification by Motion picture Association of America. Next come logos of the studio, production and distribution companies. The music maybe specially composed or it may consist of already popular themes. A cast run is also shown to publicize the stars of the movie along with the director. An attractive voice-over may explain about the plot. Trailers are highly condensed and polished advertisements.

Trailers maybe made in the studio itself or maybe contracted to outside advertising agencies called as Trailer Houses. Trailers are made with great care after doing market research and consultation with studio bosses and revisions galore before the final product is released in the market.

Free trailers are available at most Internet entertainment sites. The best trailers sites include filmtrailer.com where one can view all upcoming as well as currently released film trailers of all languages and regions.

Trailers are sometimes criticized for using clich'd statements like-?In a world where?? Some free trailers contain scenes that are not present in the movie. Some directors are of the view that a trailer must summarize the whole movie but others believe that they must only arouse some interest in the viewer.

With the free trailer revolution on the Internet, movie studios are doing brisk business in ticket sales. Attractive trailers entice people young and old to come in droves to the theatres.