I think the big one recently is the opt in ai training. A lot of people were not happy with their data being hoovered up and making so a ton of $$. So they are replacing their answers with nonsense/deleting them. Plus there's now ai bots that are on so...such a strange world.

SO is only useful if it's filled with things that help out users. If it starts getting less foot traffic, an evaporation effect occurs where more and more uses leave thereby making it even less useful.