They do, but extremely poorly. I criticize them in the OP:
> One might wonder why I don't use the fairly active [Bets of Bitcoin](https://en.bitcoin.it/wiki/Bets_of_Bitcoin) prediction market; that is because the payout rules are [insane](http://betsofbitco.in/help) and I have no idea how to translate the "total weighted bets" into actual probabilities. Betting blind is never a good idea.
> One might wonder why I don't use the fairly active [Bets of Bitcoin](https://en.bitcoin.it/wiki/Bets_of_Bitcoin) prediction market; that is because the payout rules are [insane](http://betsofbitco.in/help) and I have no idea how to translate the "total weighted bets" into actual probabilities. Betting blind is never a good idea.