Fanfic

Denis McGrath’s re-posting of his notorious anti-fanfic post (part of his week-long festival of posts that got him in trouble) made me wonder: what shows get a lot of fanfic written about them, and why? Never mind the quality of the fanfics; what’s interesting to me is that some shows, including popular ones, don’t inspire much fanfic interest while other shows just seem to compel their fans to imagine the stories that the actual writers won’t come up with.