The article opens:
One of the hardest things for me to reconcile lately is switching my brain from libraryland to retail in terms of how books get into the hands of readers, and seeing that bestsellers are often made, not born. Libraries are unique in that their collections rely heavily on peer reviews of books. I keep forgetting, after my years of library work, that not everyone in the world reads Kirkus, PW, or Booklist to make their buying decisions. This isn't a bad thing; it's just the nature of the beast. Librarians buy books for libraries in much different ways than retail consumers buy books for their personal collections. The question of bestsellers is very chicken-and-egg, and it's one that I think librarians can benefit from understanding. Amazon itself is also a different entity with different buying rules than brick-and-mortar chains. Anyway, read it. It's full of answers to (some of) the questions that keep me up at night.
It's almost a philosophical riddle: Do sales drive the best-seller list, or do best-sellers get all the sales because buyers see them on the list?
As much as we'd like to believe that the crowd picks the best books, a strong presence in retail locations -- front-of-store positioning and tempting discounts -- still counts a great deal in determining how well a title sells.