The paper Network Reputation Games by Hopcroft, J. and Sheldon, D. October 2008 gives a nice interpretation of link creation process and Pagerank score as a game with Nash equilibrium.
Generalizing the above, I wonder if Web spam and search ranking process can be jointly modeled as a game with Nash equilibrium. In other words, let's suppose that search engines make public their search ranking algorithms (ehmm) together with their demotion strategies for web spammers.
The benefit for search engines can be measured in terms of increase of market share. The benefit for content providers can be measure in terms of positions in the ten blue links or in terms of referral traffic generated by search engines. There is a non zero probability that a spammer is identified. In this case, its ranking is demoted and the referral traffic will have a drammatic decrease.
Under what conditions this is a game with a Nash equilibrium?