> Analyze posts of people giving stock tips on WSB, Twitter, etc and rank by accuracy.

Didn't somebody make an ETF once that went against the prediction of some famous CNBC stock picker, showing that it would have given you alpha in the past.

> seems to be a way harder problem for generic free form comments.

That's what prediction markets are for. People for whom truth and accuracy matters (often concentrated around the rationalist community) will often very explicitly make annual lists of concrete and quantifiable predictions, and then self-grade on them later.

Cramer is the stock picker guy. There is a well known "Cramer Effect" or "Cramer Bounce" where the stock peaks then drops hard.

Makes for great pump n dump if you're day trading and willing to ride

https://www.investopedia.com/terms/c/cramerbounce.asp

long-term his choices don't do well, so the Inverse Cramer basically says "do the opposite of this goober" and has solid returns (sorta; depends a lot on methodology, and the sole hedgefund playing that strategy shutdown)

You probably mean Inverse Cramer:

https://finbold.com/inverse-cramer-leaves-sp-nasdaq-and-dow-...