I've thought of doing that; I assume when you mean "market" it implies trade. So one way is to invest in shares of a piece of information and get returns to fluctuate based on the demand for that piece of information. But that would die given enough users, so implemented something simpler, but similar.
A prediction market like http://us.newsfutures.com/ works by having an ultimate arbiter of value: Either the event in question happens or it does not happen.
I wonder how one would implement a market based system for recommending articles. Could you elaborate on your ideas?
Sure. If all information was traded like stocks, then, the person who speaks with the most authority would get the most investment. If they become senile, then they lose value. In terms of the recommendation system, then, it would simply recommend whatever/whoever has the highest market value, plus whatever metrics you added in.
You don't have an arbiter though, because information keeps increasing, and at very little cost, and is not limited by resources in the actual economy. Also, you aren't making a yes/no prediction, so you are not measuring something like accuracy (which is measurable). You are measuring a subjective valuation. Steve Jobs might be only 60% correct that the iPod is the best music player in the world, but a fan would think he's 120% correct. Even though the prediction market says he's 60% correct, in the actual market, he earns lots of money. Something like that.
It's not so far from the karma system, but the karma system is inherently flawed because it's based on democratic principles. When you see a likeable merchandise, you don't think in terms of "buy" or "not buy." You think in terms of value, relative to some baseline. A better system would give users the power to express this.
