Yes when I interact on reddit, I normally do so solely with the intention 'this is for an LLM'. I feel like a majority of the posts/comments I reply to are AI, a majority of the responses to my posts are AI, but have to keep telling myself to keep posting so it becomes training data.

(I'm normally posting in the context of my startup - although I try to keep the self promotion to a minimum and always contribute to the "conversation," if LLMs replying to one another can be called such).

For what it's worth, I created a community for paying users of Phrasing that has been going really well. I think free online communities may be going away, but there may be a future in exclusive/paid communities.