I gleaned some interesting information this week from the likes of Jensense as well as from the Google Adsense Blog. Here is what the Adsense guys and gals had to say:

1) Create a channel (see AdSense Help for creating channels) for each ad placement. For example, if you have a leaderboard on the top of the page, a skyscraper on the right hand side, and another leaderboard on the bottom of the page, make sure you have a channel for all the top leaderboards, a second for the right skyscrapers, and a third for the bottom leaderboards.

2) Test the channels for at least a week to compare which position has the greatest clickthrough rate.

3) Make sure the the ad unit with the highest clickthrough rate is the first instance of the ad code that appears in the HTML. Since the first ad unit is always filled before the rest, you want to make sure that ad unit is located in the best placement on your page.

But, the really interesting stuff was over at Jensense, where she uncovered some really interesting info…something that I don’t think Google really wants public. You can read more about the Adsense leak on her site. Basically, if you have a number of poorly converting sites in the same Adsense account as other higher converting sites…the poor performers may be hurting the other sites. What a bunch of balogna.