All such prediction engines should include an obvious warning -- "If you act on my predictions, then all bets are off." This is why stock market predictions are

All such prediction engines should include an obvious warning -- "If you act on my predictions, then all bets are off." This is why stock market predictions are a waste of perfectly good paper: people try to act on the predictions. Jim Cramer's stock market predictions hover slightly above chance, only because of the so-called "Announcement Effect" (in other words, they aren't actually predictions). Without that, his claims would have zero predictive value.