I have a website with and AB script for test ads these were my results last 5 days first ad was 728x90 CtR: 0.34 CPC 0.27 second ad was 468x90 CTR 1.38 CPC 0.10 468x90 ad has a higher CTR means that the ads displayed on it are clicked more often, however, the CPC is lower which must want to say that the ads are worth less, my interpretation is correct? what is the best?
I am using 728 x 90 in almost every sites..its worked for me..i think you need to keep above the post title which most profitable as i believe..let try out and then decide..because it depends on geography and what type of ads displaying.
You can also try 300 X 250 ad slots they too give good results. Yes 728 X 90 has always been a good performer if u have enough space on ur site.