Yahoo using online behavior to target ads from Reuters covers briefly the "new, new thing" according to Yahoo executive vice president Greg Coleman where Yahoo banner ads are targeted based on search behavior and other activities.
I guess it depends on how you define new. As even Coleman says, Yahoo's had variations on this for some time, literally years. But the latest rev of Yahoo Impulse that he's talking about has been running since at least June of this year.
See Yahoo Testing Behavior Targeting Of Ads and Yahoo Using Search Profile To Trigger Banner Ads Over Time for more on that, as well as Yahoo CEO: 2005 Is For Making More Search Revenue & Better Ad Targeting Through Personal Info.
FYI, our Targeting Search Ads By Demographics & Behavior session at Search Engine Strategies next week will cover the Yahoo program. Yahoo couldn't get someone for that particular panel, but search marketer Dana Todd knows it well and will give a "from the trenches" presentation.
MSN and AlmondNet will also be discussing the demographic and behavioral targeting systems they have, with search marketers Danielle Leitch and Kevin Lee providing their perspectives on such programs.