The uneasy alliance: Free Software vs Open Source
Same idea, different ways
People who are introduced to the free software world often ask: is free software and open-source software the same thing? The seemingly simple question is not so easy to answer. On practical, user level these are the same thing in most cases. After all, about 70% of all free/open-source software (for which umbrella terms like FLOSS, FOSS and F/OSS have come into use to cover both schools) use the same license, the GNU GPL.
Simply put: while the outcome is largely the same, the two schools have remarkably different starting points as well as goals. As Richard Stallman puts it: Open source is a development methodology; free software is a social movement.
The crusade for freedom
As seen from previous lectures, the MIT hacker community fell apart in the beginning of 80s due to the AI Lab dividing between two competing companies. This destroyed the team spirit, many people left and one of the most promising young hackers, Richard Stallman, was one of the last to witness the disappearance of the hacker dream. Perhaps these memories are the root of his later extreme hostility towards intellectual property in all its forms.
In 1983 he started his ambitious project to create a new incarnation of the Unix operating system and deliver it in totally different terms than the proprietary software of the days. In his 1985 GNU Manifesto he outlined the foundation principles of his new methods for making software and in 1989 came the first version of its main legal tool, the GPL.
The pragmatists: open source
In January 1998, a group of leading enthusiasts of (to-be) open source software (including Larry Augustin and Eric Raymond) gathered to discuss Netscape's move to publish its browser's source code. The Open Source Initiative formed in February 1998 by Eric S. Raymond and Bruce Perens; the idea was to present the 'open source' case to commercial businesses. They sought to bring a higher profile to the practical benefits of freely available source code, and they wanted to bring major software businesses and other high-tech industries into open source. Bruce Perens adapted Debian's Free Software Guidelines to make the Open Source Definition (another example of a bridging case between the schools).
In April, publisher Tim O'Reilly organised a meeting titled Freeware Summit (later renamed to Open Source Summit) which included a lot of luminaries: Linus Torvalds, Larry Wall, Brian Behlendorf, Eric Allman, Guido van Rossum, Michael Tiemann, Paul Vixie, Jamie Zawinski and Eric Raymond. At that meeting, the confusion caused by the name "free software" was brought up. At first, Michael Tiemann argued for "sourceware" as a new term, but later Raymond's suggestion won by vote.
Richard Stallman was not invited and perhaps the grudge between persons added further to the emerging separation. Open source enthusiasts accused Stallman for hippie-minded idealism, political undertones and frightening businesspeople (Opensource.org: "it was time to dump the moralizing and confrontational attitude that had been associated with "free software" in the past and sell the idea strictly on the same pragmatic, business-case grounds that had motivated Netscape.") while Stallman responded with accousations for selling out and watering down the hacker ideals (GNU.org: "Some of the proponents of “open source” considered it a “marketing campaign for free software,” which would appeal to business executives by citing practical benefits, while avoiding ideas of right and wrong that they might not like to hear. Other proponents flatly rejected the free software movement's ethical and social values.").
Linux and Linus
Linus Torvalds, while generally considered to be an easy-going persona, has clearly sided with the open-source camp - perhaps also due to the GNU/Linux vs Linux naming controversy.
The problems with both terms
One of the main reasons for starting open-source movement is also the ambiguity of "free" in English language (however, in most languages the words for "freedom" and "no price" are clearly different). As part of the "closer to business" strategy, the new term attempted to alleviate the "no price - worthless" allegations by business people. The problem is also recognised by Stallman camp, who try to address the problem by presenting a clear definition of free software and also using the phrase "Free as in freedom, not as in free beer".
However, as Stallman points out, "open source" has also a problem in ambiguity. Misinterpretations have occured both intentionally and unintentionally, and there is a danger of shifting the focus of the model by legal interpretations. An example is Microsoft's Shared Source, which has been confused with the Open Source - but possibly never with the much stricter definition of Free Software.