Well imagine you created a novel generator that just cut-and-paste whole sentences from the Harry Potter books to create a new Harry Potter, and posted it onlin

Well imagine you created a novel generator that just cut-and-paste whole sentences from the Harry Potter books to create a new Harry Potter, and posted it online. Now, as long as this was done as a just a bit of fun, non-commercial, I feel like that likely should be allowed as fair use (whether it actually would is not the point), though borderline. If you tried to sell it, definitely too far. So I think "used for profit" is quite key. But another example is someone writing and selling a reference guide to Tolkien's mythos that catalogues the content of his novels. And we would say that should be allowed, though that could be taken too far as well, for example it could duplicate the material in the appendices to LoTR.