This is kinda funny from my perspective. In most of the world WhatsApp reigns supreme to such a degree, that advertising for it would have the same pointlessness of a Coca Cola ad. In LATAM every neighborhood, department building, workplace and school has a multitude of Whatsapp groups.
The good and functioning ones are: work related, have people that organically have become dang or are too small to receive "manual" spam / random petty fights. The "manual" spam is people sending MLM scams, annoyingly advertising their side hustles, political or religious message chains. People also will fight publicly because someone may or not have flirted with someone else's husband. Forums are eternal.
The only thing like NextDoor here is SoSafe, a community safety app, which quarantines the crazy people that see an "undesirable" taking a walk and wants to call the cops.