[sseagull]

Ads are a fundamental problem. They skew the incentives.

The search engine could, for example, give semi-poor results, making the person search again, increasing ad impressions.

An ad-supported search engine would also prioritize pages with ads that are also conveniently sold by the search engine.

As a user, I want a search engine to give me the best page with the fewest searches. An ad-supported search engine wants me to view more ads and click on them. Those are, if not orthogonal, often in conflict.

[dorgo]

>An ad-supported search engine wants me to view more ads and click on them

Is this really the case? Assuming pay per click model and rational and competent advertisers. More clicks would increase their costs and reduce the generated value per click. The advertisers would limit their maximum cost per click. This would limit the revenue of the ad-supported search engine to the previous level (from before introducing bad search results).

It is possible that more clicks (generated by tricks and bad search results) produce more revenue for the advertisers. This would (slightly) benefit both the advertisers and the search engine.

In the end and in the long run the incentives of the ad supported search engines are alligned with their customers ( advertisers ) if the above assumptions are met.