History of Short Films

Early period.
The term "Short Films" came about in North America in 1910, when the majority of films began to be made longer-running, making films of 2 or 3 minutes "short films".
Comedy became the most popular genre, and famous comedians like Charlie Chaplin and Laurel and Hardy are known well for starring in these. Short films became so popular that major film companies actually had special units just for producing them.

The Rise of Short Films.
After the 1930's fewer short films were been produced, and these shorts were produced and financed by motion-picture companies who sold them to other theatre companies. This was called block-booking and was made illegal in 1948 by the US Supreme Court. By 1955, the ban on block-booking and the rise to television, the short film industry was fading, and virtually dead. Since the 60's, short films have been reserved for independent film-makers only.

Short films today.
"Short films" now is a term used for non-commercial motion picture that is distinctly shorter lasting than the average commercial feature film. A short film is classified to last 40 to 45 minutes at the most.
Short films usually focus on topics that featue films often avoid, and they must reply on exhibitions and festival to get them in the public eye. However, short films are a regular feature on DVD discs that can be viewed after watching the main film, such as on Pixar films. For example, at the end of Pixar's film "Bug's Life", there is an animated short film available to be viewed called "Jerry's Game". Warner Brothers have also been known to do the same.
Today short films are popularly used as a first step into the cinematic art for young film makers. Because they're short it leaves room for experimenting and also because they are not viewed by a wide audience.