→ a comment to 10 Hackers Who Made History [1] by Gizmodo.
As DDevine says, Richard Stallman is no proponent of Open Source, but of Free Software. Open Source was forked from the Free Software movement to the great displeasure of Stallman.
He really does not like the term Open Source, because that implies that it is only about being able to read the sources.
Different from that, Free Software is about the freedom to be in control of the programs one uses, and to change them.
More exactly it defines 4 Freedoms:
(0) The freedom to run the program in any way you want (compare this with Windows, which does not let me start it in a virtual machine, because “the hardware changed”).
(1) The freedom to access the source and change the program (compare this to Starcraft 2 which I can’t use in a LAN-party without having everyone connected to the internet).
(2) The freedom to copy it and give it to others (compare that to all these iApps, which I can’t even backup easily for my own use).
(3) The freedom to distribute my changed versions.
This is Free Software as defined by the free software movement which was initiated by Richard Stallman and which made successes like Google possible by giving them a stepping stone to build upon: Free Software users stand on the shoulders of giants.
Open Source on the other hand is often being used as name for products which don’t even fullfill freedom (1) completely. That’s why the GNU project did not take part in the first Google Summer of Code: Google required contributors to say that they work on Open Source. In the second Summer of code that was changed, so projects can now correctly identify themselves as Free Software Projects, and GNU has been taking part in the Google Summer of Code since then.
PS: But still it’s great to see Stallman in this list!
Links:
[1] http://www.gizmodo.com.au/2011/09/10-hackers-who-made-history/