So last night I was upgraded to participate in the Microsoft Content Ads Beta program. Now I only see a way to place my ads, as an advertiser, in the content network. I do not see any way as a publisher to place these ads on my web site and get paid for clicks. The added feature for advertisers is under "Targeting", it says "Select a distribution method for this ad group." You can check off "Search" or "Content" or both. Here is a screen capture, fyi - the question-mark icon doesn't currently work for me (says forbidden access).
This is a limited beta, so many of you won't see this added feature, I believe. I'll keep you posted on what I can, as a I learn more.
Forum discussion at Search Engine Roundtable Forums.
Update: Marketing Shifts claims Microsoft pre-launched content ads on Microsoft's MSN Money Central. On this page there is an ad at the bottom that appears to be a contextual ad, but with no named provider.
This is what the ad looks like:
Also, MSN did tell me that a select few sites are pre-testing this feature, so it does make sense that Microsoft would test it on their own properties.