Don't know how integral to this thread this is, but you just might be interested in this "vignette." It's years ago; I'm on a 35-city book tour for THE MEMORY BOOK, which was an enormous success. I was visiting a large bookstore somewhere in Kansas, I believe; was doing a book-signing there. As I walked into this large store, I saw an employee arranging books on a high shelf. He was standing on a "pyramid" of books, all the same book. I saw the title as I passed - it was Solzenitzkin's (sp?) Gulag Archipelago (sp?), a book that had been on the NY Times bestseller list for some time.
After I finished my booksigning thing, I was in the manager's office having coffee, and hearing nice things, like - "Man, your book is paying my rent for me," etc. And the phone rang. I realized it was the NY Times calling. I heard the manager say, "Oh, yes, as a matter of fact, he's sitting right here in my office, just did a booksigning for me - many people came in, and yes, it certainly is still one of my bestseller." A bit more confersation, and then I heard, "Oh, yes, the Archipelego is certainly still a bestseller."
When he hung up, I was looking at him sort of quizically. I knew that when you form a stepladder with a particular book, it sure as hell couldn't be selling too well. He knew what my look was about, and said, "You know, Harry, we're allowed to return books to the publishers, but it costs money. It's more cost effective to sell what we have." And, here's the point of this long story --- "And keeping it on the NY Times bestseller list helps to sell the book."
Just thought you might find this interesting. Best - HL.