Dave Naylor posts this screenshot of Yahoo Answers serving Ads by Google above answers search results. According to the screenshot, which was sent in by a DaveN reader, it looks like the Google Ads are being served along with the Yahoo Search Marketing ads.
I don’t know, something smells fishy here. A photoshop mock-up perhaps? I’d assume that the Google and Yahoo results would be blended in together, like Ask.com does with Google or Microsoft did with Yahoo Ads.
If this is the real thing, perhaps Google is playing hardball and requesting that Yahoo actually brand the ads as Ads by Google in order to reach a specific revenue share level. Hopefully more will come of this in time. In the meantime, enjoy.