We’ve discussed friendly betting as a mechanism for forcing probabilistic and well considered prediction at the SDMB. At Justgive.org, it is possible to make a donation in honor of somebody else. https://www.justgive.org/donations/gift-donations.jsp
So I could make a 2:1 bet with Poster B. If he loses, he would pay $10 to Planned Parenthood. If I lose, I would pay $20 to Catholics in the Military. Or maybe we could develop a better charitable pair.[1] At any rate if I lost, I would receive an email, Poster B would receive an email, and Catholics in the Military would receive an anonymous or a named contribution.
The wrinkle is that there’s a $10 minimum payment. Justgive.org takes a cut. Detailed betting negotiation could occur at the Marketplace or the Game Room forum. Detailed negotiation is part of the learning process.
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[1] American Bible Society vs. the Poetry Foundation?