I have genre novels there under a pen name. I'm going to resume the second series, because I've learned enough to make it worthwhile to me. My big mistake was spending too much time on the marketing and not enough on the writing. When I swing back into that, I'm going to do almost no marketing, and definitely no ads. My books make me around $50 per month for doing nothing. It's not a great return, but I'll keep doing a book a year or so. Maybe one will take off in a big way -- maybe not. Worth the effort because it's enjoyable.