I've been following this thread with interest. As I mentioned near the beginning I read and write erotic fanfic (and I'll be the first to say I'm probably a lousy writer...) I should also say (someone quoted Bindel as saying "erotica" was a euphemism for porn which tried to dress porn up as arty) that I'm using erotica simply to mean "intended to arouse sexually" rather than carrying any connotations of art (believe me, most fanfic is about as far from art as you can get). So I'm interested by the discussion of whether written "porn" (I've put the word in quotes because obviously there are no images involved) is the same as, or as bad as filmed porn.
Filmed pornography is different from written erotica in one crucial respect because it can be and often is filmed evidence of sexual assault and abuse taking place - and the ethical consumer argument is hard to uphold because for the end user, it is impossible to tell the difference between a sexual assault and good acting - the user simply cannot distinguish on the basis of the product alone. (This is why I do not and would not watch it). It is, however, similar to written erotica in that both can and often do (in fact in the case of filmed porn, the majority does) uphold misogynistic attitudes towards female sexuality (the attempted eroticisation of rape and acts of violence and humiliation). But again, it's worth noting that written work doesn't have to be erotica (in the sense of written with the express purpose of sexually arousing the reader) in order to do this - romance books of the old-fashioned bodice ripper genre often also depict rape as a step towards the woman "melting into the hero's arms" rather than as an act of violence.
I do think though that even when (at its worst) written erotica seeks to defend and eroticise sexual violence, it lacks the immediacy of visual pornography. The act of reading puts the reader at one remove from the action and puts in a layer of interpretation whereas film puts the watcher in the scene in a way the written word cannot.
Sorry, this is an epic post and a bit of a brain dump. Going back to the original post, if you want to look at female-driven porn (and I'm deliberately not using the phrase feminist porn, for reasons I'll get to), fanfic is the perfect place for a sociologist to go looking! Fanfic is, on the whole, a female space on the internet (a rare beast, as we all know), written by and for women. And as a feminist, when I first got interested in fanfic, several things struck me. One was the ubiquity of the male gaze - a lot of fanfic is still written from the man's perspective, even though it's being written by women for women. It's almost as though we are so conditioned that what counts as sexually arousing is defined by "what a man would find sexually arousing" that even when on our own it's incredibly hard to step away from this. (A classic example would be the sort of story where there is loads and loads of build up, then the end consists of our heroine giving the hero a blow-job - where's the female orgasm in that?)
But the other thing (which I personally find terrifying) is the percentage of rape fantasy on the major fanfic sites (it's a minority interest, but a sizable minority). There are, as far as I can see, two conflicting explanations out there among women within fanfic who bother to think about these things. One, driven by "sex positive views", is that it's all down to sexual repression - we are so conditioned to think of sex as shameful that for some women the only way they can give themselves permission to enjoy sex is if they can pretend they're being forced into it. The other, which I think is more plausible, is that it's a form of society-wide Stockholm syndrome. Because of the ubiquity of male on female sexual violence in the real world, some women cope (in a cognitive dissonance sort of way) by eroticising the violence they can't escape. (As an aside, it's worth noting that among the writers and readers of rape fiction, there are quite a high percentage who have actually been raped and are using writing as a form of therapy to explore their conflicted feelings - to the extent that there are debates about whether having been a rape victim justifies enjoying this stuff, or whether it's just a sexual preference - as one woman put it "I'm fed up with having to show my 'raped-enough-to-ride card'". Personally I find myself wondering if it would be healthier for some of these women to be able to access decent therapy and get help to reset the damage to their sexuality - the tumblr blogs on this sort of thing remind me uncomfortably of pro-ana websites).
I guess where I'm going with this ramble is to ask what the best way of tackling women's own attitudes to their sexuality is. There is a view in the fanfic world that "your kink is not my kink and that's okay" - but I've never subscribed to it. I think some kinks (rape fantasies) are dangerous - both because they reinforce the women having them in a sexuality which is ultimately damaging them as individuals, and because within a rape culture, they can be used by predatory men to attempt to legitimise rape myths - "see women do say 'no' when they mean 'yes'". But I don't think (hears the ghost of Mandy Rice Davies murmuring "she would say that, wouldn't she?") that this means all written erotica is a bad thing.