Amazon's Ever-Changing Algorithms: Oops, They Did It Again

This post, by Edward W. Robinson, originally appeared on his Failure Ahoy! Adventures In Digital Publishing site on 5/4/12.

So not 12 hours after my post about how Amazon’s algorithms work, Amazon changed their algorithms again. This is a big enough deal they apparently just caused me to quote Britney Spears.

Fortunately, the latest changes weren’t a complete revolution. By all accounts, there is once again a single list seen by all customers. I’m not sure exactly how this new list works–the Avengers are still working on it–but it seems to hew very closely to one of the lists we already understood. And if you are a Select author who leans on free giveaways for sales, here is my current advice to you:

Sorry, couldn’t resist. I actually don’t think we should flee the battlements just yet, for reasons I’ll get into lower down, but this is bad news for Select authors. Phoenix Sullivan has alluded to this, and will surely have more to say herself, so keep watching. Anyway, cause for panic: the new list looks an awful lot like List B. As a refresher, here are the main mechanics (that I am aware of) for how List B works:

  • Ranks are determined by the last 30 days of sales, with no extra weight given to the most recent sales
  • Free book downloads are discounted heavily–maybe as little as 10% the value of paid sales
  • Borrows don’t count as sales

I’m not sure about whether borrows count or not on this new list. Won’t have the data on that front for a while. I am positive free books are counted, and that they’re counted at a discounted rate–feels like 10-15% of a sale. (In other words, for every 10 freebies given away, you’re credited with 1 sale for the purposes of pop list rank.) You can see this for yourself by trolling the popularity lists. You’ll see a few titles that are permanently free scattered across the first few pages. If freebies didn’t count, you wouldn’t be seeing them on the lists at all, and if they did count, you’d see a lot more permafree titles and Select titles higher up on the lists.


Read the rest of the post on Failure Ahoy, and also see this follow-up post on the same site.