Two journals Brad made about Demigod had some information, including the number of server access requests that were denied on launch. Here's one, I can't find the other. Check the Demigod Journals and you'll find it eventually.
As to this post while it does help.
1 it does not list sales numbers, and if it did it also says didn't factor in DD sales.
why, because google is too hard for you to use?
http://kotaku.com/5215528/demigod-18000-customers-100000-pirates-%5Bupdate%5D
and sorry, it was ~100,000. but my point stands.
As for this post, it is 3rd party reporting and in it, it states that it was 18000 concurrent users on the server, not 18000 copies sold. That right there negates the aurgument that has been forwarded that implied these numbers represented 18000 sales and 100000+ pirated copies.
In fact what this does illustrate to me is of that 100000 pirates most of those were probably pirates that tried multiple times with each DoS and got counted as a seperate entity each attempt.
So if anything it tends to lead me to beleive from this article solely that pirating while a big issue, isn't the issue that it is made out to be.
It only get refuted by the first article which was it appears to be written by Brad himself that even makes me think there is more to it than that. Unfortunately without hard numbers I just can't bring myself to condemn yet.