internet suddenly started offering thousands of free Twilight-like books

... fanfic, you mean?

I think I'd even predict that porn in book form won't ever achieve the same effect as being able to click through only the several most graphic frames of a 7-minute video. I think books as a medium take longer to consume and they require using your imagination to fill in the gaps, which I don't think would be quite as addictive. However, I do agree that sooner or later, the market will even out and people will begin to shoot pornographic content for straight women and we'll see if women get hooked at similar rates as men.

Actually, camera quality is getting better (on phones and things) so maybe men will start publishing photos or videos without any large production companies. Also, I wonder if men will encounter the same stigma as, for example, female teachers do when pornographic photos of them are found online. But I think part of the lag in this area is that men aren't quite socialized to be oggled the way women are? (So I'll be pretty surprised by a bunch of responses saying "No, I totally know how to be in straight woman porn!")

I googled "porn for women" to find this book I remembered seeing. I also found a relevant xkcd, an interview with a woman who writes porn, and some stuff that is actually quite hot. My husband would probably like that last one too, maybe we should watch it together some time. But don't worry, I don't feel I'm in any danger of becoming addicted.