I think one issue you're missing is that modules aren't necessarily adopted wholesale, i.e. it is common to cobble together a custom site by taking bits from here, bits from there.
So let's say someone signs your partner license for one of your specialized packages, needs to do some heavy customization, and could do so by taking a bunch of bits and pieces from some of our GPL'd OpenACS work.
Or conversely build a custom site based on one of our GPL'd packages that could benefit by cobbling in some of the work you've done in one of your commercial packages.
The licenses clash and neither is an option ...
So, yes, it DOES matter, and there's no sense in saying it doesn't.
The question, then, is HOW MUCH does it matter? I think you've seen from this thread that certainly it doesn't matter so much that people will complain, or dislike you, or refuse to talk to you, or not answer your questions, etc etc. That's not the point. It is just that code not GPL'd will always be of less use to the community than code that's not. This is not necessarily a big deal, but it may be a big enough deal that some community members won't be particularly motivated to jump in and help with such code.
Still such code is more useful than custom code done for the client that never sees the light of day, is never distributed, etc. I think the following hierarchy certainly holds:
1. GPL'd code
2. Non-GPL'd code released under another license
3. Custom code never released at all but kept strictly confidential by a client
Most of us here have done plenty of code in #1 and at least some code in #3. Thus far our community's avoided #2 but then again no one else has raised the issue with the kind of detail you're providing.
