Problem: How can a community of competitor companies share those parts of the software that is crucial for the community's success while keeping private those parts on which competitiveness depends?
Force: There is a core of the software whose proper and effective operation is of value to all members of a potential community.
Force: Control of that core is not essential to any particular organization.
Force: Intellectual property rights and/or processes have been already established or negotiated.
Force: Software is very hard to do and every development staff is too small.
Therefore: Create a place or mechanism within which the software and its development can be shared.
Remarks: The original software-owning organization needs to GoWholeHog on giving up control.