I think a solution to this might be that if instead of voting on what should be in the book, you decide on some subsidy pile of karma+money, and you use quadratic funding to decide how to allocate that pile to each post (and then giving it to the author/eventual co-authors).
You might just include the top posts in this scheme in the book, also making sure to make their scores prominent (and perhaps using scores in other ways to allocate attention inside the book, e.g. how many comments you include).
It seems more plausible to me that under this scheme users utility would be linear in the amount of votes/amount of funding they allocate to posts.
I think a solution to this might be that if instead of voting on what should be in the book, you decide on some subsidy pile of karma+money, and you use quadratic funding to decide how to allocate that pile to each post (and then giving it to the author/eventual co-authors).
You might just include the top posts in this scheme in the book, also making sure to make their scores prominent (and perhaps using scores in other ways to allocate attention inside the book, e.g. how many comments you include).
It seems more plausible to me that under this scheme users utility would be linear in the amount of votes/amount of funding they allocate to posts.