Reminds me of that paper about searching for time travellers on the internet: https://arxiv.org/abs/1312.7128

Unfortunately, the internet is filled with ARGs and pranks. You can't really trust a "message in a bottle" kind of communication, it's likely to get lost.

Considering the current state of humanity, I would say it's a big risk looking for those kinds of messages. 99% chance of scam or prank.

Nothing. Absolutely nothing on the internet can be trusted.

In the loosely defined category of message in a bottle, what may be the most popular ever is ongoing: PostSecret.

https://postsecret.com