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Aspects of this criteria might include whether or not the system solves the free rider problem, what barriers to innovation are present, what barriers to interaction with the proprietary world are present, etc. (Need, of course, to more precisely define the free rider problem.)

Another way to think about this is 'if I contribute to the commons, can someone take my code without giving me some sort of value back, either in the form of more code or more data?'