Kobo bestsellers ranks affected by reads, not just sales.

[GeoffR]

This is perhaps of more interest to publishers than most of the readers here, but I've noticed lately that when I finish reading a book I bought from Kobo and sync, the book seems to get a boost in its genre rankings a short time later, even if it is a book that I bought a long time ago.

That may be why they have renamed the "Bestsellers" genre lists to "Trending Now" -- they no longer just reflect which books are being bought, but which are being read too.

(Kobo ranks the books separately for each country, so it might be hard to see the effect of individual purchases/reads if you are in a populous country, or reading popular books. I am looking at the New Zealand site.)