I shouldn't be surprised. This sort of thing happens all the time. An author will strike gold with a plot or a theme and for the next few months to a couple of years publishers will do their best to copy that author's popularity with clones.
It happened with Harry Potter. It happened when the Lord of the Rings movies came out. It happened with Anne Rice and Buffy the Vampire Slayer and the "Bodice ripper" romances of the 80s and it's happening with now with erotica thanks to the success of Fifty Shades of Grey.
It's not just new authors hoping to jump onto the erotica band wagon. Publishers have started reprinting erotica novels that have been out of print for years and putting them back onto the shelves in a "Here's hoping!" moment that people will pick them up as well.
And it's not stopping there. Plans are in place to rewrite old favorites like Jane Eyre and Pride and Prejudice into erotica.
How thin is the line between inspiration and plagiarism? Is it wrong to write a piece of fan fiction and then try to get it published?
Yes and no. You cannot copyright an idea. The plot, theme, and characters in Twilight can be seen in tens of thousands of other books. Twilight and Fifty Shades of Grey are too very different and at the same time very similar books. Edward and Christian are in my opinion completely different characters. Ana and Bella are very close but do have their differences. The relationship between Ana and Christian is radically different and at the same time similar between Edward and Bella. Both are intoxicating, intense and frightening.
Do we really need another clone of them though? I was watching the Hunger Games the other night and I said to my husband "You know what's good about this? It's not Twilight fan fiction. It's completely original." And he agreed.
You cannot copy right a character or a plot or a theme. But after a while things became stale and flooding the market with clones of Fifty Shades of Grey is eventually going to turn the public against erotica again.
We don't need more Twilight fan fiction being sold in bookstores. What we need is more original, thought provoking books like the Hunger Games that are so original, so fresh, that when you finish you go "Wow!" because you've been on a real adventure.