I'm thinking of purchaisng a XenForo license, I was wondering if this feature already exists in XenForo, whether it is planned or how difficult it would be to implement. I want to contact other people in my niche and ask them to promote my forum, in return, the members that they referred would be shown an advert from the referring person. For example they could have the link: mydomain.com/forum/signup.php?ref=ReferrersName which would record who referred the member upon signup and then display an advert based on the refferer? I didn't see the referred by option on he signup page on this forum, but is it just disabled? Any clarification (or advice) would be much appreciated. Thanks!