true_INFP - 9:43 am on May 8, 2010 (gmt 0)
Comparing CTR to determine whether interest-based ads perform better than regular ads (which should be the real topic of this thread) is totally and utterly flawed, incorrect and misleading.
See my previous post to understand why. Google wants to earn more. That's why they serve ads with higher eCPM (not CTR).
Comparing earnings (as opposed to comparing eCPM) is again misleading because earnings increase or decrease as your traffic increases or decreases (whereas eCPM acceptably compensates for this).