“Nostur uses follows + follows of follows to filter spam and bots, and it uses likes and reposts from follows uniquely ranked to create Hot and Gallery feeds.” - https://habla.news/u/fabian@nostur.com/nostr-web-of-trust

Article also talks about the ‘Algo’ on Oddbean.

Yeah I think a few devs have stayed away from using zaps in trending algos for that reason.