This is from google Adsense blog. http://adsense.blogspot.com/ "Use the 300x250 Medium Rectangle. This ad format is one of our best-performing ad units, and many advertisers use it when creating rich media (image and video) campaigns. Again, you'll benefit from the increased competition for your ad space. " Check http://blog.e-webtemplates.com to start earn money now.
That's IF you have video/images enabled. In my opinion, the 336 square brings in the most for just text....
An ad is an ad, does it really matter wich format it appears in? True, you need a laege box for videaos to appear, but if they are all text ads, i would have thought it wouln't really matter.
I agree to this... Also, if you select the image ads, there will be some video ads too and that slows down your website considerably...
Both the 300 or 336 rectangles do better than other formats in heavy text content sites, according to my own experience.
depends on blend in factor , the unit hasnt got anything to do with it, personally ive always had link units better performing.
It depends upon the layout of the site and blending. My best performing ads are vertical banner and Wide Skyscraper.
i have good success with banners (images), never tried that box although i heard from lot of ppl that it brings more clicks.