Regarding more examples, I think that any action which someone could say "I would do this but what difference is one person's action going to make" is a candidate for a good campaign. More examples I can think of mainly relate to conservation (energy, water etc.). I also think this platform could help power boycotts of companies which could be a very powerful use (but also with a risk of becoming dangerous as pointed out by Ramiro). I actually think that this alone would be a very powerful use for such a platform.
And regarding my second issu...
To be honest, I haven't considered that at all. I can definitely imagine that if a platform like this were to become popular it could start organizing campaigns that don't necessarily conform with my values. However, I think that with minimal moderation those could be dealt with, but I would have to walk the line between removing truly bad ideas and ideas which I just may not completely agree with.
But this is still a problem that I only think we could even face if such a platform reached a large critical mass of users, which is pretty far down the road.
I think the dynamic you describe where betting for real money “incentives [people] to try to set the most unfavourable odds they can for the other party” is correct, but also good. Two rational actors will only engage in a bet if they believe it is +EV for each of them. In a zero sun bet, this is only possible if each actor assigns sufficiently different probabilities to the event in question. So actually in the case you described about the £10k bet, useful information was conveyed. You demonstrated that you were not sufficiently confident in your claims t... (read more)