I really, really despise advertising. It can't disappear soon enough.
To make this comment a bit less ranty, I'd like to add something: some people believe that ads don't work on them. I very much disagree. Ads DO work. That's exactly why I don't want anywhere near me.
Optionally, adjust the price according to rating. The higher the rating the lower the payment for interaction with the ad. Let unpopular/unsuccessful ads/advertisers pay more for the same customer.
Let me adjust the price and rating thresholds to exluce low priced / low quality ads.
Keep track of my purchases to build my reputation among advertisers.
That's where we started. It's a solution, but only for one side of the market. It leaves a lot of potential inventory and revenue on the table.
The solution is less, but better ads sold at a higher cost. This is generally what makes search advertising work. Popular keywords garner a premium price, which in turn prices out those who are looking to manipulate the advertising platform with misleading ads. Higher cost ads means that less ads need to be sold to make a profit. Unfortunately, such an elegant solution has yet to be seen for content based websites, and so massive amounts of ad placements are added to websites just to break even.