It seems like every few years a big name author will holler something about how evil, heinous, and morally wrong fan fiction and fan fiction writers are, and then the Internet gets all upset and shocked, and then the author is shocked that people could get so upset.
Just about every science whiz can tell you how he or she took apart the TV or the radio when they were kids just to see how it worked. To see what the world was made of. Well, when I was a kid, I took apart fairy tales to see how they worked. To see what the world was made of.
For most of us, fanfiction is a non-issue. Even for midlist writers. We will never be popular enough for people to play in our worlds with any frequency. The problem for us is getting people to read and care about our books that much in the first place.
I have always been delighted when told there was a piece of fanfic inspired by a book of mine floating about. I don't read it for legal reasons, but I'm thrilled to know it's there. Someone cared. Someone loved it enough to spend their free time writing about it for free.