Gentle readers as much as five minutes farther behind the times than I am may need to know that fanfic is amateur fiction written as extensions to and with the characters of a more famous, probably professional, work. There's a lot of it, for television shows and movies and comics and books and probably the more vivid commercials; most of it is awful. The general idea produced the Metamorphoses, and there are lot of pastiches in the juvenilia of subsequently respectable authors, so it isn't new.
Slash gets its name from the Virgule: it adds a love-relationship between some characters, e.g. Yorick/Hamlet. Usually it's a homoerotic love-relationship, and most of them are sexually explicit. I have worried for some time why there were so many straight women busily writing homoerotic fiction, not because I am against homoeroticism or inventive reuse of cultural materials, but because one grown practitioner told me - a while ago, on a defunct website - that they had to write romances between male characters, because they couldn't possibly add enough to the female characters to make them credibly interesting. Now, that's clearly not true in general, because we've had decades of re-envisionings of various myths with more vim in the women - low culture or high; Modesty Blaise to The Robber Bride; I should mention the Heroides to be fair. (Maybe that's low culture to medium. Since, for a while, terribly high fiction hasn't expected the characters to actually do anything but talk, women have not been at the same disadvantage in it: consider The Golden Bowl.) I have been wondering why anyone would say it was true in a fiction universe as pliable as Star Trek or Harry Potter. Maybe it's a cover for the reading woman's version of the watching man's enthusiasm for lesbian porn scenes. Possibly there' s a de/marg(anil)ization of the gaze and subjectivity, or it could just be a efficient way to get the sexually uninteresting characters offstage. Most of it's too drecky for me to care.
I read Lust Over Pendle because Kate Nepveu recommended it as a comedy of manners, and hey, it is one: of the Avengers era rather than that of Lady Windermere's Fan, with a '20s English country detective air and some Buffy. This surprised me the more because it's an extension to the Harry Potter books. (I've only read the first Potter book, some time ago, didn't much like it, & haven't seen the movie, but I understood the plot despite an admirable lack of expository dump.) One great advance on the originals, to my taste, is that Hall sets the book in the character's (just) adulthood; it also has active and opinionated women, including older wiser & definitively experienced ones; and the central relationship is credible but not the whole of the plot.
So wrote clew in
SF&F.