You should be sure to look at Google AdSense For Domains Program Overdue For Reform -- And Yahoo & Microsoft Should Also Take Note
, which I posted today. In short, it summarized (and for members goes deep) into how you can't block Google AdSense For Domains becuase Google -- wrongly in my view -- considers this part of Google AdSense For Search rather than Google AdSense For Content.
These names are just killing me. Honestly, let's just call AdSense for content AdSense, AdSense For Domains DomainSense or DomainPark and AdSense For Search AdWords, so that it's much clearer these are three very, very different products.
Then, if you want to buy search targeted ads, you buy AdWords. Want content? You buy AdSense. Want parked domain traffic? You buy DomainSense. Want to carry Google ads? Then you can also decide which of these programs to carry.
The entire I bought AdWords so I got AdSense For Content, Search & Domains but I can exclude ads on Content but I can't on Search and oh, Domains are part of Search, it's nutty.
Overall, as GuyFromChicago says, some people may find parked domain traffic converts. But it clearly is NOT the same as search targeted traffic and so like the content program, it ought to be a completely separate buy/marketplace.