I'm thinking of using some javascript to set a quickly expiring cookie that keeps track of how many pages are viewed by a visitor in say a 24 hour period. On each pageload the JS would look for this cookie, and if the cookie isn't present or the count is low, it will show Adsense. Otherwise it will show some CPA offer from Commission Junction or whatever I can dig up. The thing though, is I don't know whether visitors tend to click Adsense on the first pageview, or after they've gone through a few pages without finding what they're looking for. I'm a little torn on the idea, so I'm looking for some input.