The paperback reprint of my novel Blade Dancer debuted at #4 on the SF paperback bestseller list. At least, I'm assuming fourth place by counting down from #1; whoever typed it up has me and China Mieville starred versus numbered.
I can't account for my excellent showing, other than knowing that the hardcover did very well last year. Even then, Blade Dancer was not given any special promotion that I know of. The publisher bought an ad in Locus and sent out the standard amount of reviewer copies, but I think that was it. Except for an excerpt on my web site, I didn't do any promotion for the hardcover or the paperback in July. I don't make public appearances, don't do readings, booksignings, or go to conventions. I've abandoned all self-promotion except for my web site, and I haven't touched that in a year.
I'm not posting this to smirk at all the writers who do self-promote. I'm just as stumped as everyone else is as to why my SF sells so well when I do nothing but write the books. I'd like to think I'm writing what people want to read, but that can change from one book to the next, and you should never make that assumption. When you're too confident of your readers, you get lazy and self-indulgent. In this industry, every book is a fight for numbers and readers.