I've started to sell over there with SF. I'd say their algos a little more rank-driven than Amazon, but your sales rank doesn't decay quite as fast--although there are some definite cliffs built into it. You'd think this would lead to nothing but swift and irreversible downward spirals, but as long as you don't fall away too fast, they seem to do an all right job providing plateaus.. their alsobots seem like they might be kinda effective, and they almost certainly have email recommendations or something.
Also, either they have a lot of reporting delays, or day to day sales are much more inconsistent than Amazon. As long as you're not running into a cliff, Amazon's pretty steady day to day, but BN can take wild swings--sell 50 one day, 20 the next, assume it's all over, but then the next day it's up to 40. But some people just seem to go on selling one month after the next, so maybe it's steadier than it feels.
When you're not selling there, it feels like a hopeless wasteland, but it's a big market, and every genre sells there. If erotica and romance have traditionally had the easiest time getting started, I bet that's because their fans are more prone to hunt down the specific stuff they want. With other genres, you have to work harder to get your stuff in front of readers--permafree, regular new releases, sales, advertising, whatever--but it's certainly not impossible. We just have fewer tools than we do at Amazon, and fewer people breaking down how to do it.
