Yeah, I suspect that a lot of the decline represented in the OP's graph (starting around early 2020) is actually discord and that LLMs weren't much of a factor until ChatGPT 3.5 which launched in 2022.
LLMs have definitely accelerated Stackoverflow's demise though. No question about that. Also makes me wonder if discord has a licensing deal with any of the large LLM players. If they don't then I can't imagine that will last for long. It will eventually just become too lucrative for them to say no if it hasn't already.
