I strictly use Nextdoor for recommendations from my nearby neighbors for reputable contractors, setting up Housing Association meetings, or other meetings relevant to my neighborhood area. I have also used it for emergency cases; like some neighbor's pet running loose in the neighborhood in danger of getting hit by a car, or eaten by wild animal. I have used it to give neighbors a headsup, be aware of suspicious person in the neighborhood. I never use Nextdoor for chatting.
People complain about getting too much mail, which is easily remedied with settings provided on the Nextdoor website. Have someone being nasty to you, or someone you are insulted by because they decide to be the spelling monitor and are attacking you? There are settings to block that person. Honestly, some people will complain about everything and are never happy. One can please some of the people some of the time, but one cannot please all of the people all of the time. Some people complain, and there for they are. If people would take the time to learn how to use the website properly, it truly is not a bad website.