A thread at Digital Point announces says that one user "Just Beta Tested MSN's New Adsense-Like Network" apparently its called ContentAds.
"To be honest is was actually pretty sweet. I am not going to talk about any specifics until is goes open beta but I feel it is a huge improvement in certain aspects. I am just waiting until I can take it for a spin on some of my websites to really get a feel for it. I wish MS would just give me a job so I can help them step it up some more. For any platform for content publishers you really need to focus on the filtering and reports. Those are the two area I use the most so the most attention should be paid attention to them. A close third of course is the ad creation process. Watch out for MS, they are not going down without a fight."
SERoundtable says "Content Ads was open to large publishers and to a limited set of adCenter advertisers to opt in. Microsoft continually expanded the ContentAds availability for advertisers but never really expanded the publisher side of things. "
There has been no response from Microsoft rep adCenter 411 either. So till Microsoft announces, things are still uncertain and details unknown.