[Freesteyelz]

Originally Posted by albn

I am not really sure about exactly why other than since the style was grandfathered as GPL, it cannot be used in a proprietary environment and billed as GPL because of conflicts. That's the best of my understanding.

Ahh, simply put...

GPL software and proprietary software can interact with one another without causing conflicts, protecting both copyrighted works and adhering with GPL's terms. I think vB is concerned with program linking and the fact that the style codes will have to be modified in order to comply to vB's system and as a result will be considered derivative work. It is defined as (Copyright Act, 17 USC 101):

A “derivative work” is a work based upon one or more preexisting works, such as a translation, musical arrangement, dramatization, fictionalization, motion picture version, sound recording, art reproduction, abridgment, condensation, or any other form in which a work may be recast, transformed, or adapted. A work consisting of editorial revisions, annotations, elaborations, or other modifications, which, as a whole, represent an original work of authorship, is a “derivative work”.

GPL terms refer to derivative work as "work based". Because phpBB issued the style as GPL, whatever modifications you do to the style will be subject to GPL terms. With vB in the mix, it too will be subject to the GPL terms. Noticed how the two programs are linked to one another? Again, if you're doing it for personal use it wouldn't have been an issue. Because the style would have been distributed to the public that's where the conflict begins.

I hope that helps.