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.
Not mine, but there is a certain compelling logic to this: https://bruces.medium.com/the-mysterious-visit-of-mr-babbage-by-bruce-sterling-2017-7c941028c4d8
tl;dr - accepted history is that Charles Babbage designed a series of mechanical computers in the mid 1800s, and the underlying theory behind them would go on to influence work a century later when the technology had caught up to the idea, but they were never built. There are a bunch of coincidences and unexplained meetings that suggest that maybe he sold his plans to Italy who then built one of his designs in secret. This is also supported by modern attempts to build a computer from his plans - there was 1 measurement wrong across tens of thousands of parts, and it worked perfectly. Babbage was a skilled engineer but to get all that correct, on the first go, entirely from theory is maybe a bit much