Placement reports, are new reports from Google, that show AdWords advertisers who opt in the content network, where there ads are being displayed.
SEW Forums moderator, Discovery, said, he spotted Yahoo within his placement reports:
Started getting this in my placement report this past week
Only 12 clicks this month at a mid level CPC... no conversions!
This begs the question, is Yahoo using Google AdSense to supplemental their inventory?
Forum discussion at Search Engine Watch Forums.