This just in via the Google AdSense blog:
Extending AdSense for domains to all publishers
Many publishers have approached us looking for a way to monetize their domains, and today, we're excited to announce the expansion of AdSense for domains. This product allows publishers to earn revenue through ads placed on undeveloped domains.
With AdSense for domains, users can find relevant information rather than see empty pages or "page not found" errors. Today we present ads, links, and search results on the pages, and may add other useful information in the future. To ensure positive user experience and the quality of our network, these sites are monitored for policy compliance and prohibited from using text and images designed to confuse users.
Advertisers also have additional opportunities to find their customers, and ads on these pages convert well. In addition, we regularly receive requests from advertisers who have found domains to be an effective way to reach their users.
The product will be initially rolled out in phases to English-language AdSense publishers located in North America, and we'll expand to additional regions and languages in the future. To check whether AdSense for domains has been enabled for your account, log in and visit your AdSense Setup tab. For more information, please visit our Help Center.
Not sure what impact this will have on the parking companies. I guess it depends on the contracts Google has with them and on the revenue share it will be offering to domain owners. But one should think the share will be higher without the parking services as a middle man.
This also shows that you should not be dependent on one business partner: If Google is going to directly compete with the domain parking companies they may be forced to look for alternative ways to monetize their clients' traffic.