Sorry this took me a little time to check into, but I wanted to get as much info as possible for you.
First of all, this spam you have on your forum is not the work of an affiliate – it would be a lot easier to take care of if it were. It is an advertiser we use – but it’s not even him directly. The advertiser in turn uses services of all different search engines. What you see on your forum is the result of their work.
Tomorrow I’ll be meeting with the team which works with the advertiser directly, and will have the opportunity to check with him if there is any way to prevent this from happening in the future.
Sorry I couldn’t give you a more definite clear-cut solution, but hopefully tomorrow I’ll be able to see what’s possible to do to prevent this.
Marcia