Because animation is very time-consuming and expensive to produce, the vast majority of animated productions are made by professional studios. When the Hollywood animtion industry entered a decline during the 1960s (see Hollywood Animation: The TV Era), a small but steady number of independent animation producers kept the art of animation alive. They produced a number of experimental films that pushed the boundaries of the medium, experimenting in ways that Hanna-Barbera and Disney didn't dare to consider. A number of independent animation producers went on to produce mainstream animation, and they became successful in their own right.
Many independent animation short films are largely unknown; they are rarely seen outside of independent "art house" movie theaters. Collections of independent films have been gathered for theatrical viewing, and video release, under such titles as the Tournee of Animation and Spike and Mike's Sick and Twisted Animation Festival.
The rise of the Internet in the 1990s and 2000s saw an exponential increase in the production of independent animation. Personal computer power increased to the point where it was possible for a single person to produce an animated cartoon on a home computer, using software such as Macromedia Flash or Autodesk, and distribute these short films over the World Wide Web. Independently produced Internet cartoons flourished as the popularity of the Web grew, and a number of strange, often hilarious short cartoons were produced for the Web.
In the late 1990s, an independent animated short film called The Spirit of Christmas was produced for under $2,000 by two artists, Matt Stone and Trey Parker. This film was widely distributed on the Internet as a pirated cartoon, and its phenomenal popularity gave rise to the popular TV animated series South Park.