But why not make the prediction public? That' the part I don't understand. (I came to ask the same question as GP.)
It seems that it's used on Twitter to prove that you were right about something, and so people should trust your foresight ability. E.g., this tweet here: [1]
How does keeping it secret change things? If it's about something that is secret that you know about, well then having foreknowledge is not that surprising. Is it so other people can't steal your prediction and also be right, so you're not as special?
Indeed, as far as I can tell, that tweet was a prediction about global consequences of the Coronavirus. How does keeping that secret help anyone at all, besides saying "ha ha, I was secretly right all along!"
I guess I can also think of some very specialized cases, like getting a hash of a patent you're submitting to prove invention date. But I think I'm being dumb not coming up with more obvious reasons that must make this desirable to lots of people..
Because making a prediction publically can affect the event itself. Either in a positive feedback loop (Elon Musk tweets "Gamestonk" => Gamestop stock goes up) or negatively (in any hypothetical situation where an adversary wants to frustrate you, allowing them to know your prediction also allows them to work against you).
Imma going to go and make a whole bunch of predictions, wait a year, and then only reveal the ones that actually came true.
Now I'm a genius, right?
This is basically similar to an old common scam, where you would mail 100 people, and 50 would say 'buy this stock it's awesome', and another 50 would say 'sell this stock, it stinks', and to 50 of those people, you're going to look like a genius, and to the others, you're just another scrub.
Now I could go and make several predictions for the top 100 stocks, planning for every possible move, and then as they come true, start to reveal those predictions and BAM, I'm a fucking genius, give me all your money, and I'll invest it for you.
I think these always depend on generating the hash and publicizing it ahead of time. Otherwise yes, it's worthless. But I think most people realize that.