Following Tolkien, we often refer to the imagined worlds in which works of fiction take place as “secondary worlds”. But in the last half-century or so, many amateur authors have created, and shared widely, works set in what we might call “tertiary worlds”—worlds that are to a “secondary world” as it is to our “primary world.” This is a phenomenon commonly known as “fan fiction”, “fanfic”, or in some circles simply “fic”.
We can divide fan-fiction authors into at least five (significantly overlapping!) groups, based on their reason for writing it.
For some authors, fan fiction is a stage in their development. They can gain experience writing in someone else’s world, about someone else’s characters, then move on to fully original fiction. This is similar to the stage of “wish-fulfillment fantasy” many would-be authors go through. Most of this isn’t much worth reading, any more than anyone else’s first efforts (like stories written for grade-school assignments), but for those so inclined it is invaluable practice. (“How do you get to Carnegie Hall?”)
There are others, who (like me) write because they have stories come to them, but for whom the stories that come are set in worlds and feature characters whom they did not themselves invent. Some ideas are so insistent that they have to be written—in the community these are sometimes called “plot bunnies.” (Possibly because they sometimes seem to breed like rabbits?)
For a third group of authors, fan fiction is a form of transformational criticism. (Personally, I’ve seen more of this in the Bujold fandom than any other, which is not surprising given the significant (especially given her genre) amount of “traditional” critical work spawned by her novels over the last few years.) These authors, of all the groups I’ve identified, are the most likely to produce consistently high-quality fiction.
A fourth group are those who, as readers, voraciously desire more—or different—stories than the “canon” contains, and so meet this desire by writing the stories themselves. This happens in fandoms where the “canon” is finished (Jane Austen will never write a sequel to Pride and Prejudice, for example), where the author writes too slowly for the fans’ impatience (the Harry Potter fandom, before the seventh novel was released, for instance, or the Wheel of Time fandom now), or where the author simply leaves an opening for a possible tangent and doesn’t follow it. Sometimes, in fandoms whose “canon” has passed into the public domain, these stories are even published.
Lastly, some readers take it upon themselves to fix what they see as the author’s mistakes. Literature is, after all, a collaboration between writer and reader, and some writers don’t hold up their end of the (implicit) bargain. (I recommend Bujold’s essay “The Unsung Collaborator”, published in Dreamweaver’s Dillemma.) If an author (for example) creates a world that fires the imagination, and fills it with compelling characters, but then turns the story in directions that do not make any sense in the slightest … who can blame a reader for writing the story that she should have written in the first place? In my opinion, this explains why there is so much Harry Potter fan fiction on the Internet, far more than the size of its fandom as a whole warrants.
Fan fiction written as “practice” fiction probably should not be distributed beyond a few friends, teachers, and family, for the sake of any potential readers (there’s far too much content of dismal quality on the Internet already!), though on the other hand wider distribution may lead to faster improvement of the author’s writing because more readers give feedback. Muse-led (or “plot bunny”) fan fiction need not be distributed, and given Sturgeon’s Law combined with the low cost of “publishing” on the Internet I’m sympathetic to authors’ desire to control or prevent its wide availability and distribution.
I’m less sympathetic to any suppression of the other three groups. Transformational criticism, like the more traditional kinds of criticism, cannot (if done well) but enhance the fandom. Stories written because of the desire for “more, more more! Now, now, now!” are a reasonable solution to that problem, and suppressing them is likely to make the readers lose patience altogether and move on to some other fandom instead of waiting for the next canonical installment—it is not a good business practice to turn down free publicity. And in the last category … an author who drives her readers to fan-fiction by producing inspiring but in one respect abysmal fiction has lost all my sympathy, particularly if those frustrated readers produce fan fiction that is better than the original.