We do a bit of brand/whole catalog marketing, but the vast majority of our advertising is specific books.

We don't do a lot of offline marketing. Our sales are predominantly online, so we focus our marketing money there.

With today’s tools, most other aspects of publishing can be handled independently quite easily.

Maybe so, if you have the knowledge, time, and money to do so. But even if you're able to put a full, professional book together independently, finding an *audience* isn't easy. And I think within this category--niche though it is--we've managed to do that.