Rather than just basing the results on the highest bid like they did before, they are now factoring in the ad's CTR. I see this as a positive improvement on their network. It will be interesting to see how this effect everyone's daily spends...
I wasn't aware this was a recent change, however I did notice that I'm not receiving hardly any network interestials anymore.
It will be a positive change for some. But negative for alot of others. I may take another look once the fallout of this change is worked out!