Google has formally announced the expansion of AdSense for domains, a program which allows publishers to earn advertising revenue from undeveloped (read parked) domains. As you might imagine, the many domain parking companies are not so pleased.
Google by all accounts is going to be turning the world of domain parking on its head. Presenting not just advertising, but links, search results and according to the post "other useful information" which will provide a much better experience for both users and, most importantly, advertisers. Google apparently believes in the opportunity for advertisers so much, they are touting a case study with SEM solution provider Efficient Frontier.
Publishers and domainers will need to abide by the policies outlined by Google in relation to site and ad behavior, trademark issues, etc. Adsense for Domains will be rolled out in phases to English-language publishers located in North America. Current publishers can check to see if their account has been enabled via the AdSense Setup tab.