The rumors have been building for a week now, here is the first thread i have found on the topic, started by Brett Tabke at WebmasterWorld, under the featured title name Yahoo Contextual Advertising Program. Silicon Valley Watcher came out with the most recent story, they always start a big buzz on things. The first rumors on this came from Waxy.org, where they think that the Yahoo! ads look like what is found at this blog.
All I have to say at this point is http://publisher.yahoo.com/. More to come...

Comments:
Loren
03/08/2005 05:53 pm
They're using Constant Contact for their sign up and email management :p
Eric Giguere
03/12/2005 07:31 am
I've put together a quick analysis of the Yahoo! ad program at http://www.ericgiguere.com/articles/yahoo-ad-program.html for those interested in more details.
Toronto Student
03/22/2005 08:54 am
lets hope competion sets google straight!