it's great at first, then Amazon realizes it's erotica and makes it harder to search for! Now I only see a few a month!
I do -- most pulled down right now. But if you do the Amazon route, do the Smashwords route too. It lets you publish in multiple markets simultaneously (do Amazon separately, though, and consider doing Kobo separately) and it's friendlier to Erotica in general. That said, Amazon will generally be okay so long as you're pretty up front about what you're publishing.
If it's literally a derivative work, containing intellectual property owned by someone else, then no. You can sell followups to public domain works (so if you want to publish your Psyche the goddess from myth is seduced by Bob Cratchett from "A Christmas Carol" story, you're fine... and I sincerely want to know about it because I would so read that), but not derivative works based on IP still under copyright. This is why Fifty Shades of Grey (which was originally self-published on Amazon) had to strip out its original fan fiction elements (Twilight characters, mostly) and replace them with Christian Grey and Anastasia Steele. Sometimes that means creating an 'expy' with similar but slightly different elements (Batman's under copyright? That's fine -- this story stars 'The Blood,' a vigilante who was a billionaire traumatized in his youth who uses horrifying vampire imagery to terrify criminals as he fights to clean up Arsenal City! Totally different guy!) and sometimes it means filing the serial numbers barely off (Batman's under copyright? No problem -- this story stars Batsman. Brew Swain was the heir to a wealthy Cricketer who was murdered in front of him, growing up to... you get the idea.) The very slight name changes and the like are more likely to distract your reader, though. At the same time... you may have noticed that the filmmaker Alex Braun (in particular, though far from the only one) produces pornography starring copyrighted and trademarked characters. When that happens, you'll generally also find the word 'Parody' in the title -- The Avengers XXX: The Alex Braun Parody, say. That's because parody is protected speech -- according to theory, any of us can write a parody of Naruto and sell it. However, in a practical sense, Wicked Video has a lot more money than most of us and are much better positioned to fight off a legal challenge. It's not a hill worth dying on, when you can so easily tweak the characters a little or a lot and then work from that. The legality of free fan fiction, like a bunch of us write right here on CHYOA, is an open question in the American legal system. If DC were to send me a cease and desist over The Luthor Agenda, I'd cease and desist pretty fast because I'm poor and they're huge, but it's not really been established if they have a legal right to shut my story down. If I were to bet on a test case, I'd bet on the IP holders winning, mind. The thing is, most IP holders are indulgent of fan fiction because they recognize its value both culturally (yes really) and as implicit (and free) advertising. The 'deal' there is you don't make money at it. When money gets involved, and you make enough noise about what's going on... then you end up with an Axenar situation, with Paramount cracking down on Star Trek fan films. (Not here to debate which side was right in that situation, for the record. It's just a convenient example.) If Amazon discovers that you're selling an unauthorized derivative work they'll pull your listing, and Smashwords will generally do the same. This, by the way? Is why I have a Patreon. I can't sell fan fiction, erotic or otherwise, but I can invite people to support my writing in general, and that gives me the time to write fan fiction which I post freely. Does that seem like splitting hairs? That's what happens in the American (and other) legal system sometimes. If I sold The Luthor Agenda or The Seductive Spider-Harem, I'd be directly infringing on DC or Marvel's intellectual property. If I post them for free here on CHYOA or on AO3, then I'm posting in that grey area fan fiction currently lives in -- having a Patreon doesn't inherently move my stories out of the grey area into the infringement end zone. More than you wanted to know?
I think, you forgot to attach the references for that dissertation. I admire your dedication for writing this. Very informative.
...yeah, I get enthusiastic and I babble. Obligatory disclaimer: I Am Not A Lawyer. These are rules of thumb. And thanks!
At one point, yes -- but the secret to Amazon, Kobo, Smashwords -- all of those -- isn't to have a huge hit book. The secret is to have the 'long tail' you hear about -- if you get thirty or forty pieces (short stories, novellas, novels, etc) into the different channels, then selling a few copies of each in a pay period (usually monthly or quarterly, depending on the store) translates into dozens of sales per pay period -- plus the people who decide they like your stuff grabbing the rest of what you have. Plus, as you build your long tail and your rep, sales go up in general. Which is another reason to put your ebooks into as many stores as possible. Amazon will give you a nice boost to your royalties if you give them exclusivity, but that doesn't trump having sales all around the world in every conceivable digital archive. It's always surreal to learn someone in Slovakia is reading the story you wrote about an Incubus ravishing a college student. (Side note -- all of these markets all have a toggle to indicate if something is adult content. Never ever skip or lie about that, especially if you're publishing through Smashwords but even if you're doing something like Kobo or Amazon globally. The stuff that they'll flag as adult and hide from certain searches in America can be shockingly illegal in other countries. If you've taken the appropriate precautions to label your work as adult/erotic/pornographic in nature, then it's (largely) on the stores to keep them out of those places. They have systems for that. If you don't label your work, as a self-publisher it falls back to you. Is it likely to be a problem? Maybe not. If it is a problem then it could be a wildly disproportionate one.) So, yeah -- it was profitable for what it was at that point, and I expect that as I rebuild the long tail it'll be profitable now.