> Прежде всего на этот рейтинг влияет количество скачиваний, ожидаемо подскакивающий после
> новости о релизах, это очевидно, если понаблюдать за рейтингами в момент
> выхода новостей.

Вижу только "HPD" (Hits Per Day) и ни слова про скачивания:
https://distrowatch.com/dwres.php?resource=popularity
> Originally, each distribution-specific page was pure HTML with a third-party counter at the bottom to monitor interest of
> visitors. In May 2004 the site switched from publicly viewable third-party counters to internal counters. This was
> prompted by a continuous abuse of the counters by a handful of undisciplined individuals who had confused DistroWatch
> with a poll station. The counters are no longer displayed on the individual distributions pages, but all visits are logged.
> Only one hit per IP address per day is counted.

Т.е. весь "рейтинг" - кол. просмотров дистро-сайта на дистроватче.