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.
I got another one (that's pretty much a fact) in order to get facial recognision, fingerprint sensors, etc working you have to login with your ms/apple/google acc, on windows 7 you didn't have to... now why would you need an online connection to setup a piece of physikal hardware with local sofyware??? It's pretty simple: apple, google and microsoft know your face, your fingerprint, your voice, your location, etc