At two extremes, say: If I read your books and use them as a strong foundation from which to write stories (e.g. I don't do any worldbuilding, & just re-use se

At two extremes, say: If I read your books and use them as a strong foundation from which to write stories (e.g. I don't do any worldbuilding, & just re-use settings/characters without my own introduction), it seems reasonable that my derivative would need some kind of license from you. If I read your books and write book reviews about them (including small excerpts from the book), it seems unreasonable to require your explicit permission. I think the website mentioned (which displays stats about a book, and a couple of excerpts) falls far closer to the latter case than the former case.