not sure about what site you are referring about but that calistyle site is NOT
I'm looking at this page:
http://calistyle101.com/forums/freeb...p-freepay.html
the first ad displayed is your left column skyscraper - not the leaderboard below the first postbit
although, the skyscraper earns you the highest return per click
it's the leaderboard that gets you the highest ratio on clicks per # of impressions
NOTE: I'm NOT referring to the first ad that you see. I'm talking about the first ad displayed (fetched) by your browser.