> With nonfiction, it doesn't make sense at all. If you are interested in a topic, look for a book about it.
I think it is more complicated than that. I am interested in many topics, but at many different degrees of interest, and I don't have time to look for high-quality books on all of them, especially the lesser ones. However, I may see a book on a bestseller list that happens to coincide with one of those interests, especially one that I haven't read much on recently, and it may make me interested in reading that book when I might not have come across it otherwise.
(Edit: I realize high-quality != popular, but it's often a reasonable proxy for casual interests.)
I think it is more complicated than that. I am interested in many topics, but at many different degrees of interest, and I don't have time to look for high-quality books on all of them, especially the lesser ones. However, I may see a book on a bestseller list that happens to coincide with one of those interests, especially one that I haven't read much on recently, and it may make me interested in reading that book when I might not have come across it otherwise.
(Edit: I realize high-quality != popular, but it's often a reasonable proxy for casual interests.)