Make sure to read the disclaimers about this page at FreeOpenServicesDefinition.

Interestingly, neither the OSI nor the FSF definitions really go into why freedom or openness is actually good, which I think contributes to the lack of clarity around each.

O'Reilly has defined the core user freedoms as (slightly edited from his version):

• use

• build on (what I've broken out as ecosystem participation)

• adapt (FSF uses modify)

• participate (what I've broken out as direct contribution)

• fork
• switch (Sun uses 'leave')