Don't bite my head at this but because Fifty Shades of Grey is coming out as a film, I finally decided to read the novel (curtesy of my addicted friends), and I felt some similarity to something I've read quite a while back. Possibly 4 years ago.
I did a little bit of research and found out that it was originally written as a FanFiction and then turned into a novel. God, I'm so late on this one -- like I didn't even hear about this.
Then I got some questions going on in my head:
1. What separates an AU story from your own original story?
2. What's your personally opinion about using your FanFiction and turn it into a novel?
3. Why don't you write the AU story as your own novel? Why do you write it with the characters who have been created by someone else?