I know I've seen some forum members make this recommendation at times here and there, but it's a point that I think hasn't been emphasized strongly enough -- if your site accommodates the 300x250 medium rectangle ad format, or you can redesign your pages to accommodate it, make every effort to do so. In my experience, this is truly the best-performing AdSense ad unit when it's used the right way -- placed prominently above the fold, blended in with content but still looking like an advertisement. I've recently implemented (roughly a month ago) this type of ad format into my site and the increase in earnings has been very satisfying. So that's my tip -- if there's any way you can, use the medium rectangle!
Recent post explains it all http://adsense.blogspot.com/2008/06/five-steps-to-optimising-your-adsense.html And well if anyone would do a test they would find out long time ago that 300x250 is the highest paying unit.
I don't know about 336x280 cause I always used 336x250 ...It works really well..One more thing you need SE traffic to boost ur adsense income
I wrote about this not too long ago. http://www.mickmelseo.com/20080312/which-performs-better-336x280-or-300x250/ In short, most advertisers that build image/video ads prefer the 300x250, so using that on the site will likely result in higher paying ads. On the other hand, many sites report a slightly higher CTR with the 336x280. The key is to try them both and see which one generates the best eCPM.
Would anyone be so kind as to show a live example of a blended ad? I'm gonna give this a whirl, so any help appreciated, cheers.
Thank you mickmel, anyway having both sizes side by side would also help in not looking like two same ad blocks, giving it some sort of differentiation which would benefit, 336 on the left and 300 on the right.