What is core to Open Source? As the OS community is tested by Microsoft and it's "shared source" FUD on one end, and by the market on the other, it's important that it figures out what is absolutely core to its mission, what it should never change, so that it's flexible enough to change everything else (thanks to Jim Collins for this observation). Richard Stallman lays this out in his four freedoms.

Freedom 0, the freedom to run the program for any purpose is critical to continue the open, end-to-end architecture that supports innovation. This freedom is being threatened by Microsoft's licensing terms, authentication measures, .NET, and the DMCA.

Freedom 1, the freedom to study how the program works, and adapt it to your needs, is critical to end lock-in, the economic strategy that has done most to limit software innovation and productivity. The DMCA challenges this, as does proprietary code. OS and the business community need to get much more sophisticated about lock-in, and should take an active stand against this at an infrastructure level.

Freedom 2 (the freedom to redistribute copies) does not seem critical to me, but part of freedom 3 (the freedom to improve the program) is critical, because again it fights lock-in.

This notion of lock-in is so important that I feel it deserves its own essay, that I'll write soon.
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