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.
Political extremism isn't real (specifically in regards to left wing "extremism"). Its a social construct created by the capitalist class to convince workers that left wing ideologies are scary and having your elections be between two liberals is "normal". If you ignore that ideologies like Anarchism become common sense. Why do we need lords and masters, why do we need the tyranny of capitalists and the cruel rule of "democratically elected" leaders? Ultimately we do not, the economy would be better if it was owned by the workers and world better if every person was free to be the master of their own life. Capitalists and politicans fully understand this, thats why they pump everyone with propaganda so they can keep their positions of privilege and power.