Press release: Get More Targeted Leads with Content Match
This content-targeted program is launched with a 20% discount till September 21, 2003. It is not immediatly clear where it will be used besides MSN. I don't know either on what grounds the association between content and ad is decided. The example about Norah Jones looks simply keyword-based, maybe in tune with MSN's page template (in the PR screenshot "Norah Jones" is the page subtitle.) Google seems to try to "understand," rather that being told, what's the page is about.
This new service looks like a (small-scale) answer to Google's Premium AdSense service for bigger sites, rather than something competing with AdSense at large, which refuses personal sites (though site owners had had various success getting signed on, "personal site" or not) but places no restriction based on traffic.