Look at the BSRs and the number of reviews.
Working on my analytical tool, I routinely watched the first page of BSR-sorted books: BSR #1 – 1 review (the data in the tool is delayed for a few minutes), BSR #1 – 1 review, BSR #37 – 0 reviews.
I thought it was some glitch, but no. It is the reality: BSRs less than 50 and almost no reviews.
And now the most cryptic thing – all such books were published two days ago, May 12th.
Please, somebody, explain it to me. Why May 12th?