I was browsing through Adsense Help pages and noticed a page devoted to ad sizes. There I learned some thing that I did not think of before, Ad orientation. According the AdSense, wider ad sizes tend to outperform their taller counterparts, simply because of their eye-friendly or reader-friendly format. When we read or glance at some thing, we absorb information in "thought units," several words at a time in the case which contains text. So wide ads let us comfortably read more text at a glance without having to bounce between lines like in a vertical ad or a narrower ad.
With their knowledge in ad space, AdSense team has this suggestion;
If positioned well, wide ad sizes can increase your earnings significantly. The sizes we've found to be the most effective are the 336x280 Large Rectangle, the 300x250 Medium Rectangle, and the 160x600 Wide Skyscraper. Keep in mind that while these ad sizes typically perform well, you should use the size that best complements your pages.
Following video explain the fact;
So why don't you try with your website. If you are not a AdSense member, you can signup at
Google Publisher solutions.
