I have some azoogle ads on one of my websites, and I thought a quick and easy way to stop the search engines from following the links would be to slap a rel="nofollow". Bad idea. I generated about 200 clicks with no leads before removing the links. Right after I removed the nofollow, I start generating leads... I guess this makes sense, because the nofollow tag is typically added to places where users can spam. I just did not know that azoogle(and possibly other affiliate sites) could detect when a user came through a nofollow link.
Did you ask azoogle if the nofollow would be an issue? My guess is it's not and what you saw was/is just a coincedence.
I don't think there is a technical possibility for them to know if a surfer came from a nofollow link. Azoogle would have to crawl your pages to know that you're using nofollow links. It must have been a coincidence.