Wad has actually answered that on here a couple of times.....will someone put the bloody search back up!!??
I actually asked the same question before I signed up.
Anyway, all the download links are fake. They actually go to a page and set a cookie and do a redirect to the real .exe. That cookie is set for the domain of the sign up page. So u get credit when they sign. Thats how he explained it on here before anyway.
Some of the "History Killer" type progs with a trial do it this way and others build an exe on the fly with the ref in it.
This means you shouldnt download the exe thinking it has your ref code built in and serve it from your server or spam it directly etc.... It wont work... It has to be downloaded from a link on the pages built by ICOO
Hope that helps.