First of all, did you check the PPCIncome.com website? It has a lot of good info on it. In particular, go to the home page and click on the FAQ link.
Also, here is a link to a thread from DNF that had a lot of great Q&A:
http://www.dnforum.com/showthread.php?s=&threadid=25080
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With DS, you need to have nameservers for your names (not your own personal ones, but you need nameservers somewhere) and it is best if you also can forward your traffic to a url. If you want a combo page (sale and search), then you need to have a page somewhere, probably one for each domain.
With Afternic, you are putting your names on their nameservers and serving their pages. That would not work with DS. I have not done very well selling at the old Afternic. I don't know about the new Afternic. I suggest that all of your Whois data should tell people out loud that your name is for sale.
I earn around $10/cpm at DS with mostly non-adult domains. Decent adult domains tend to earn more like $20/cpm (based on unique visitors). $20/cpm = $20.00/1000 unique visitors = $.02/unique visitor.