PPC_Consultant - 6:42 pm on Jul 23, 2008 (gmt 0)
one hard way around the issue is to run the campaign in different time intervals and go from there. I chunked out the day into 3 segments, midnight to 8AM, 8AM to 4PM, 4PM to midnight, and ran the account at different intervals on different days. It became pretty obvious which campaigns had better ROI on a certain segment versus no change at all. And since Yahoo does not have timer function, you will need to build your own Yahoo API application to turn things on and off for you..