Hmm, okay, I can see that. I guess I wasn't paying much attention to the frequency of prediction markets articles on here. From that perspective, I see where you're coming from. I was miffed by the "here" in your "I really wonder whether privacy would actually be the answer here", because I assumed it meant the story under discussion, but I suppose it's a fine comment if we think of this page as a general discussion of the industry.

As to your exact proposal, I do have some criticism (less hostile this time). I don't think it would be easy to get people to do trades when they can't see the price. It's not enough to just ask everybody for limit orders, and then only pair off the ones that cross, because you're asking people to tie up capital on a trade they don't even know the price of.

Basically, somebody does a trade on a prediction market not because he believes he knows the probability, but because he believe he knows it better than the market.

Is there a way in your proposal to get around this limitation?