This is very big news in the domain industry; will undoubtedly have an impact on those who buy traffic from, or sell traffic through, enhance. May also have an impact on the other 2nd tier ppc search engines.
The title for this post is incorrect and misleading. It gives one impression that in future, the Bids from enhance.com will be serverd in these 50,000 + domains.
There is already a thread [webmasterworld.com...] regarding Marchex acquisition of Name Development Ltd.
Marchex's operating businesses include Enhance Interactive (http://www.enhance.com/) and TrafficLeader® (http://www.trafficleader.com/). Some of their other business includes GoClick.com (recent aquisition)
Marchex has not revealed how they are going to use the recent acquistion of 50,000 + domains (currently these sites use the high paying PPC program from Overture).
I'm sorry if the headlines seem misleading. They weren't intended to be. As well, I didn't realize the other thread had already been started. Different names for the buyer. Seems rather unlikely they wouldn't start running some of their own ads on these domains, now that they control them. Regardless, it will be interesting to see what happens next.