I run a visa agency in Bali. The part of my week that has nothing to do with visas goes into scrapers on Apify, and one of them reads Amazon's Best Sellers and New Releases lists — the ranked top 100 of any category on 21 marketplaces, over plain HTTP, no browser and no login.

That Actor health-checks itself every night, which means I did not have to run an experiment to get a panel: 40 runs of one list — Best Sellers in Electronics on amazon.com, 50 rows a time — spread over 24 distinct days between 12 October and 9 November, 1,609 product rows. Some of those days carry two or three runs minutes apart, because a failed check gets retried. Those accidental duplicates turned out to be the most interesting rows in the file.

Rank is a cache. Ratings counts are not

Amazon's help pages say the Best Sellers lists are "updated hourly".…