Mythopoet
Auror
That said 50SoG is a best seller - BECAUSE it has a publishing house behind it.
Actually, 50 Shades started as Twilight fan fiction posted free on the internet. Then the author revised it to take out the blatantly Twilight aspects and self published it. It was a huge hit as a self published ebook so a big publisher snapped it up. They didn't make it a best seller. They eagerly cashed in on the success it already had because they couldn't care less about the quality of a book as long as it sells well.