@ Leyor
+1, and thanks for the article!
I find it funny that this started out as a "Wow, authors make more when their books sell for $25!" I realize that Rowling is rich and all that, but I have to think that most of that $25 per book was NOT going into her pocket. I'd venture to guess that the majority went to marketing costs...
...that probably weren't all that necessary after a certain inertia had been established, but god knows we MUST set "opening day" records, or the publisher will be sad.
That's just me guessing, though. I don't have special insight into the publishing industry. It would be interesting to break down how much of her wealth came from the book sales alone and how much from merchandise, movie tie-ins, etc.