Word of mouth (goodwill, loyal fan base) doesn't come from an algorithm, nor fit in one. I dread the day when/if I have to start worrying about it.
No, and it also doesn't come from a one-day sales spike, either. Nor does it come overnight. It builds, quietly, in forums and in discussion rooms. Sarah Pinborough, at Mancunicon, reckoned she'd rather have someone go in and tell their office that they liked the book rather than post a review on amazon (I'd rather like it if people did both ).
But to ignore the importance of marketing to bring about enough sales to start word of mouth seems a little off kilter.
Bottom line (sorry, wait for the depressing bit) there are something like four million books on Amazon US. People have to find the sodding thing and read it before they can talk about it. And that's where your marketing comes into it.
An example. Our town had fireworks last night, and we have a little beach about ten minutes walk away with a good view to the castle and loughshore where the display was. Down we went, and there were about 10 people on the beach (it was rush hour, usually there's no one), including a nice chap there to take photos. We got talking. He's a writer. So am I. Chatted about each other's stuff, exchanged facebook contacts and there you go, word has spread again.
I look on it that there's a big lake out there, of readers. And you want to reach them. Each little drip is another stone in that lake, and you want to fill it with ripples. But the stones have to get in there first of all - and, frankly, at the start no one but the author (and their publisher, if they have one and they're lucky to get some promo) can put the stones in.
So, I say yes to everything. Interviews, forum posts, guests posts, blogs, the lot. If it's promo I thank the person kindly and take it.
Is it paying off? I think, judging by what people tell me here and elsewhere, yes. It's not bringing huge sales yet, but my name is getting out there. And each time it's mentioned, each time someone sees it, there's another ripple.
Incidentally - on a tangent here, but bear with me - early on we thought about removing Abendau from the title of my books. It's hard to say, to spell and I don't have the easiest name to remember, either (or it's memorable, but a pig to spell). It was very much a case of balancing up the unique series identification vs being a little easier for people to remember.
I'm glad I stuck with it. There is no other Abendau on Amazon, and very few Zebedees, either. It can be found. Because that's the key to everything - being found.
To also give hope (sorry, getting boring now perhaps) - I was chatting with a very level-headed, sensible writer at Mancunicon and was introduced to the concept of break-out books and I've been thinking further on it since.
GRRM - had loads of sf out before GOT. Pat Rothfuss - took off on the first book. It's easy to say Pat got lucky, or just wrote an amazing first book or whatever, but that might not be the point. The point is, one had their break-out on the first book, one later on, and it made no difference. Just because your first, second, third, fourth, whatever doesn't go viral, it doesn't mean your next won't. Keep writing. Get stuff out there. (Please, please, get stuff out there when it's honed and ready - you can't make it if no one can read you). And sooner or later, something might happen.