sfatih - 2:16 am on Nov 10, 2005 (gmt 0)
Personally, removing the ads from the lowest ecpm pages helped me. They were about 20% of all pages and my overall earnings increased slightly instead of going down. After a few weeks like this, I made a second change by leaving only 1 ad block on each page, and it caused a spike in cpc although the ctr dropped to half. Still, the overall earnings increased over the first improvement. It has been at this state for more than a month and going good so far - one ad block per page and no ads on bad performer pages.