I’ve spoken to other published authors before who have frequently told me that publishers look very poorly upon fanfiction and — in some cases — will force their authors to take legal action against fanfiction writers for copyright infringement. One of my favorite authors specifically says on his website to send along fanart, but don’t show him any fanfiction, because he’s not allowed to look at it and his publishers consider it infringement.
With my own publishing contract, I wanted to make sure that any fans I might gain for my book would be free to create and share alike fanart and fanfiction that they made. At first the publisher was a little uncertain about it (fine with fanart but not too thrilled with fanfiction, as tends to be the case with publishers), but after consulting their lawyers and listening to my requests, they added to my contract regarding copyright infringement and legal action against infringers that fans would be considered safe and uninfringing as long as they aren’t commercializing their work related to my book.
Basically, if I hadn’t said anything, anyone writing fanfiction about my characters would have been infringing the publisher’s rights and open to legal action, even if they weren’t selling or charging money for it. But now that the contract is changed, that’s gone.
All in all, a win.
I wish more authors would speak up about this!