Open source software is software whose source code is published and made available to the public, enabling anyone to copy, modify and redistribute the source code without paying royalties or fees.
Open source code evolves through community cooperation. These communities are composed of individual programmers as well as very large companies.
Examples of open-source software products are:
Programming languages include:
Operating Systems (OS):
Open-content projects organized by the Wikimedia Foundation — Sites such as Wikipedia and Wiktionary have embraced the open-content GFDL and Creative Commons content licenses. These licenses were designed to adhere to principles similar to various open-source software development licenses. Many of these licenses ensure that content remains free for re-use, that source documents are made readily available to interested parties, and that changes to content are accepted easily back into the system. An important site embracing open source-like ideals is Project Gutenberg, which posts many books on which the copyright has expired and are thus in the Public Domain, ensuring that anyone can use that content for any purpose whatsoever.