I’ll go first: r/kitty. One of the hundred grillion cat subs back on Reddit, the culture in this one was you posted a cat picture, and the only word allowed in the title or in any comments or replies was “Kitty.”
Someone is using that subreddit for covert communications, I just know it. Either on the level of “if u/PM_me_your_nostrils posts an orange cat, we attack at dawn!” or there’s some steganography going on with the pictures, but that subreddit was too stupid to be as active as it was.
iirc last check it was about 50/50 people vs bots. The problem is people running bot farms or AI generated channels know exactly how to tailor content to the various algorithms used by big social media companies and thus actual human content is actively burried.