Interesting discussion.
I think that it would be very difficult to generalize about people's interest in BDSM. For there are nearly as many shades of interest in these matters as there are stories on this site.
I'm fairly confident that nearly every one of us is regularly surprised by the kinds of things, and the kinds of stories that turn other people on. I also have a feeling that many of the men who frequent our little corner of the world would be surprised by how many women drop by; and the women, like the men, are probably coming, psychically, from every conceivable kinky corner of the erotic cosmos.
I suspect that there is one great divide that separates most of us here into two camps; I think that there are a good many people here, of whom I am one, for whom these stories are entirely fantasy. Despite the high level of sexual violence in my stories, I have no interest whatever in engaging in any sort of dominance/submission or violence in real life.
Others do, of course. And as long as it is consensual, that is fine with me (here, life differs from art -- generally speaking, I don't care for BDSM stories which are largely consensual).
Personally, I think the differences that separate our various friendly factions are at least as interesting as the differences that separate us from the more vanilla world around us.
How many of us are satisfied with the safe, vicarious thrills that we find here? And how many actively pursue such thrills in the real world -- or long to?
Boccaccio