Free and open-source software/Intro
From AdCiv
Free and open-source software (also known simply as Free software or Open source software) is software created by loose networks of people who collaborate for mutual benefit. The software they produce is also made freely available for anyone else to download, use and even modify because they also supply the human readable source code used to create it.
Making source code available means anyone with the programming ability can customise the software for their own ends or contribute to the development project directly. Others can help by reporting bugs and helping with documentation or translation efforts. So this encouragement of interaction between users and developers, and (some) users becoming developers, creates a positive feedback loop in the software's evolution. Open source is becoming a very prominent method of software production and poses a serious challenge to commercial products - as the quality of open-source software approaches and supercedes commercial software, how will software companies compete with free?
Although 'free software' is available free of charge, the 'free' in the title actually refers to the user's freedoms, which are the freedom to use the software as they wish, the freedom to modify it and the freedom to redistribute it. It should be also noted that 'Free software' is not the same thing as 'freeware' or 'shareware' which although they might be free to download, do not usually come with source code and cannot be freely modified or redistributed.