I know prediction markets are sometimes requested, i.e. posts whose content is "How much do you bet that X will happen?", but it's hard to implement because who's gonna moderate and decide if and when X happens.
These type of posts would enable a swarm intelligence that would provide great unique value to SN though.
So I suggest a modified "prediction market" that does the same thing, instead of betting on outcomes the betting is always on "what everyone else will pick", with outcome and rewards distributed when the "poll" ends.
What that would enable is a very interesting type of question: "What do you think fewest others will bet?". It forces swarm intelligence.
For instance, it's not so interesting to have a list of bitcoin and 5 shitcoins and ask "Which coin has greatest potential; Place your bet on which you think others will choose". Obviously everyone will pick bitcoin. But asking the XOR of the question, "Which coin will fewest people choose?". Talk about informational!
Also, I think you are replacing one problem (oracle problem) with another problem (sybil resistance). You would need to KYC your users so they can't just create more votes out of thin air and create a lot of votes for every vote they didn't pick.