I just saw !germanrap@feddit.de as #6 in Communities/All (sorted by Hot) (web archive) on feddit.org. This feels weird because the feddit.de server has been down for almost 2 years and the community seems to have no content (the home server cannot be contacted to verify but no posts seem to have been federated to other popular instances like feddit.org) and obviously never will have. As for the subscriber count, feddit.org keeps its own tally, which is currently (archive) at 64. This does not include new subscribers after the last federation with feddit.de, except local ones. These can also be checked separately, and the number is… one. This suggests that only one person ever subscribed to !germanrap@feddit.de in the past 1.5 years (as far as feddit.org, a 1k-weekly-active-user instance, is concerned), and yet the community is very high in Hot for a day.

Obviously, the visibility of the Communities/All (by Hot) list varies by client, for example Voyager shows it unsolicited as “Trending communities” in the Search pane, and even though Lemmy devs didn’t include it prominently in default Lemmy UI, they definitely have considered the value of this list in mind since it’s made the shortlist in Lemmy’s API benchmarks.