What it literally is, for those who don't know, is Twilight porno fan-fiction, but with the names changed.
I watched an Alex Day video where he read the forward of the book that stated the original work was named something different and posted on the internet, where the main characters were Bella and Edward.
So if you think about it, 50 Shades of Grey is wildly successful for being Twilight fan-fiction porn. And I guess all Stephanie Myers has to do to get some extra cash is make fan-fiction off of that book, but with her own Twilight characters, and the two authors can feed off of each other for the rest of time!
And I sincerely hope Emma Watson elects not to take on a film adaptation. For one thing I'd probably lose respect for her seeing as how she tends to distance herself from skeeviness and the overall over-sexualized hollywood type, and secondly it's a little too creepy to see an actress who I can still remember seeing for the first time as a little girl all grown up and starring in soft porn. Then again I guess I'm not that much older than her, but still. Just say no Emma.