Context: I'm currently in the midst of constructing a non-profit foundation for Tahoe-LAFS and also a business of my own. The business doesn't have any special access to licensingit is so far a pure open source strategy. (Perhaps a bit of a rare beast nowadays.)
Although, there would be nothing preventing my business from in the future *buying* a license to use Tahoe-LAFS in a proprietary way from the foundation! I think Mozilla gets some funding that way, although I'm not sure. If anyone could confirm or deny I would appreciate it.
(Of course the Tahoe-LAFS Software Foundation, which is not controlled by me, would have to agree to sell such a licence.)
Let's see, so you are strongly averse to letting your code be used in proprietary software at all. That's easy to understand. So for example if the non-profit foundation sold rights to make proprietary derivatives then you wouldn't want to contribute your patches to that project at all, right?
Does this also imply that you never contribute patches to any code base which isn't copyleft? No BSD/MIT/Apache-licensed contributions from you?
Another interesting twist to this whole thing is the Transitive Grace Period Public Licence. That licence is like the MIT/BSD/Apache licence in that it allows people to make proprietary derived works, *except* that they are required to release their derived work under the TGPPL within 12 months. So it is a sort of time-delay copyleft. How would you feel about contributing code to a project that used that? http://tahoe-lafs.org/~zooko/tgppl.pdf
Tahoe-LAFS itself is currently distributed under your choice of GPLv2+ or TGPPLv1+: