Thanks, Ian. I didn't plan to tell the poster about my findings, if he sent me that PM. I'd have referred him to a publisher instead, because I don't have much of a clue what makes readers tick and what makes a story/book interesting. Apparently, mine are not what the general public is looking for, judging by the sales. But then again, I might be with the wrong publishing company for the kind of books I'm writing.

It's easy to tell what publishers are NOT looking for: Anything underage (even in a flashback), scat, bestiality and snuff. Not because that doesn't find any readers, but because credit card companies are heavily cracking down on anything with such content. And credit card companies are key players when it comes to online trading.

Anyway, looking at the reader's count on the stories here on the library I'd say the way to go if you want high sales with BDSM-books is non-conseny. Sex sells, and hard, rough sex sells even better.
Apart from that it should read easily, the story should flow smoothly and the editing should be good enough so that readers don't get annoyed by errors (but that is of course the editor's job, not necessarily the writer's. Although some publishers don't do anything in that regard, afaik.)

A book should also have a decent length. Anything below 30'000 or even 40'000 words will most likely not get published. Apart from that, I really don't know. I write about what I like. That seems to interest a few people, but not that many.
Might be better if I wrote for the readers and not mostly for myself, but since I don't have to live from selling my smut I just can't be bothered. I'm writing for the fun of it and period.
Anyway, I think it's still a good idea to keep your readers in mind when writing.

And finally, read those who sell lots of books and do the same. If you can, of course