[mattw]

I would have been very interested if this had gone to court to test the GPL purely in the context of themes/plugins, because to me that's the grey area. As it is, I wish (for the sake of both parties) that the matter could be settled without legal intervention. Now that it's been demonstrated that Thesis outright copies and incorporates portions of WP source code, it seems unlikely that a court decision would directly answer the question of plugins, because it wouldn't need to. (I don't think anybody argues that such copying isn't a GPL violation.)