Wow. Amazon's review system is broken.
I just now read the verification of that in the Reviewer Forum. While frequently flavored by spite, calumny, contempt, and mean-spirited attack posts, the forum DOES offer some inside information to outsiders like myself. And here's what I just found out, and why it might be important.
Reviewers are ranked based on the number, timeliness, helpfulness of their reviews, and whether or not they are a 'Verified Purchaser.' That last means they purchased the product through Amazon; KU loans are excluded from that category. The higher a reviewer is ranked, the more impact their review will have on a product. A side effect of this system is that top reviewers (the top 10,000) will often be solicited to write reviews for products, and there have been scams associated with the practice, including reviewers selling positive reviews.
On or about July 26, ALL reviewer ranks were frozen. Prior to that, rankings changed daily. I had peaked at 5,559, I believe, then slipped through non-participation to 6,179. And that number did not change, even though I started reviewing again and getting helpful votes. I finally researched it, after yet another day of unchanged rating, and found it's like that for EVERYBODY.
WHY IT MIGHT BE IMPORTANT (to authors): No one is EXACTLY sure what the algorithm is for determining the rank of books. We DO know that rank is important, because random pickers like to get the highly ranked books. Other than that, sales figures and reviews are used to determine the rankings; a review from a top 100 reviewer is going to mean more than a review from a person who only writes one review, thus putting their name at the bottom of the list with a ranking somewhere in the vicinity of 35,000,000 (my ranking for my review of Amanda'a "Nocturnal Origins" was 14, 360,604 on 10/28/14). As far as I know, we do not know how Amazon weights reviews vs sales.
BUT: a short freeze evidently happened once before, due to a software glitch, and it got fixed. We are coming up on two months for this freeze, and so far, NOBODY at Amazon has even admitted it's happening.
So I think: we are in for a re-set. I could be wrong, but I think that some of the loopholes in the reviewer system (like pay for review) got too egregious, and so they are going to dump the old system, and implement something new.
In the short term, this might impact book ratings and sales, but in the long term, I think it's gonna be okay. Amazon NEEDS a review system in place in order to run; that isn't the case since July 26, so a fix WILL happen.
Who knows? Maybe it will take into consideration Kindle Unlimited as some fraction of a verified purchase. That's how it works with money.