How?

Dead easy.

I implemented this tactic myself yesterday on one of my sites and my CTR has gone up 300% and it hasn't been 24hrs yet. Needless to say I'll be spending the rest of the morning making changes to my Adsense ads across my site network.

What is it?

Sorry can't resist a little intrigue.

It's very simple. Using the Leaderboard banner 728 x 90 I added small images/photos above each ad at 140 x 100.

These photos are broadly related to the ads and draw the eye of the visitor to the ad. Which the ad alone maybe would not do. Once their eye is drawn they read the ad text below the image and they are much more likely to click.

Google already knows of this tactic and I know a number of people have approached them via email before implementing the images. Obviously nobody wants their account suspended. The good news is Google are fine with it, for now at least. Although a few warnings have gone out with regard to animated images not being appropriate. So no flash or animated gifs!

Now I hope this is new information to you. If so I know it's going to be damn useful. And most of all profitable!

The benefit of this over Google's own 'image ads' is, you choose the image for one and the basic text ad appeals for another. As I'm sure you're aware text ads work better than image ads. This seems to work better than both separately by combining them together, the major boost comes from you being able to select the most relevant image to your site content.