Open source

Open source is a software development method where the source code of an application is freely available to the public and is often developed by the public as well.

Success stories
Some of the most successful software in history has been open source. The Firefox internet browser has gained about a 30% market share among internet browsers, the first to break Internet Explorer's virtual monopoly. Wikipedia is build on Mediawiki, an open source wiki platform.

Apache HTTP Server is the most popular web server software. PHP is a very popular programming language, particularly for websites. Linux is an open source operating system.