The primary feed for DS is Google. You can check that out easily. Go to a DS landing page and click on one of the top keywords. Do not click through to any of the advertisers. Then open another browser window at Google.com. Search on that keyword. You should see pretty much the same results for the paid search on Google that you see on a DS landing page. However, DS sometimes does redirects straight to advertisers that they work with (when the payment to the traffic owner is greater than the payment you would get from the Google or other feed). Also, DS uses other feeds in addition to Google.
I believe that DS and all other services receiving Google or Yahoo feed and reporting income are estimating income during the day. They have real time data on traffic and keywords and use recent data to project the revenue from those domains.
I know about other providers: ND, Parked, TrafficZ, Streamic - They all update real revenue after 48 hours, but I have not noticed that it is the case with DS. Btw do you know what is Revenue Share with DS?
If that is the case, then it may be that DS assign arbitrary values to clicks. This is good in some ways because it makes revenue more predictable for the user.
Nope, DS is a VERY, VERY large customer for Google. My Google rep has told me they have a special contract and get bid prices in the feed. I'm also told they won't do this anymore. That's what I've been told by a Google employee anyway and it does make sense as DS bid prices never change once posted.