Wow, what a mess! Standard lost dog fare, but also a lot of busybodies nitpicking about neighbors' municipal code violations, suspicions of people who don't look like they "fit" the neighborhood, and general bickering in every comment thread.
NextDoor seems like a good idea, until you execute and it turns out the power users are busybodies holed up at home who have way too much time to micromanage the goings-on in their neighborhoods.