I should do a better job of looking at dates before I start reading. I didn't realize this was a necro thread until I got to the end.
As long as I'm here, I'll weigh in on the review issue.
Sales are complicated. There are a wide variety of factors that contribute to sales, and we don't have enough data to really determine how those factors interact and which are more important.
I've bought a fair number of new releases without reviews. But if I see a book that's been out a long time without reviews, it does make me question the book's quality. Knowing that reviews of creative products are inherently subjective, I'm not necessarily swayed a lot by the nature of the reviews, though if there are a lot of negative ones I'm slower to buy.
Looking at my books, the top sellers tend to be the ones with the most reviews, though that could be a chicken-and-egg situation. I have noticed sales slow on books with few reviews when a negative one pops up. And on what was in general my best launch ever, the book's first review was a one-star, and sales immediately tanked. Other reviews came in, all positive, and sales rose again. These experiences lead me to believe that reviews do indeed influence buying decisions, though they are far from being the only factor. And remember, Amazon lets people filter searches by star ratings, meaning users can essentially make your book become invisible, no matter what its rank, if it has an average lower than four-star and the users are searching for four-star or higher.
On Bookfunnel, I think sales depend on how often you do sales promos on the same book. The audience doesn't necessarily grow fast enough for you to keep getting sales on the same book, particularly if a lot of the same authors are in your promo pool each time. But a new first-in-series release or standalone release still does reasonably well for me on BF. Newsletter signup promos are better each time I do a new reader magnet. (The last time I did that, sign-ups quadrupled from the previous month and remained high for a while.) But when I keep offering the same reader magnet, activity gradually dies down.
With regard to sponsoring BF promos, I'm doing that for the first time this month, so we'll see. Given the fact that we can see author's promo averages when they sign up, how long are those freeloaders really going to last? It seems as if they'd get into fewer and fewer promos over time. And although I might not kick people out on my first time, I know some authors kick people out who don't share and won't take them in future promos. Non-sharing seems like a problem in our power to correct.
With regard to Bookbub, yeah, BB does occasionally take books with few Amazon reviews. But at one point, when I was doing research, I looked at several newsletters in a row. Books with very few reviews were decidedly in the minority in the newsletters I checked. Diving deeper, I found that the books almost all had something unusual going for them. They often had reviews places other than Amazon. (One, for example, had over 1000 five-star reviews on GR.) Some had atypically large number of reviews on some of the other outlets. Some had high rank even before the BB. Back when I was looking, some of them were from USA Today bestselling authors. In other words, large number of Amazon reviews or not, I couldn't find many that weren't atypical in some ways.
