In DNF's rules, there are restrictions on the placement of affiliate links (i.e. only Exclusive members may place an affiliate link in their signature, only mods may put an affiliate link in a posting).

But something that struck me was, what criteria must a link fall under to be considered an "Affiliate link"?

Is it any link which may cause the mentioning user to financially benefit?

Is it a link of another person's product in which the mentioning user has signed up as an affiliate? Or can it be the mentioning user's own business?

Need the benefit which might be realized from placing the link be financial? Or can it be any sort of benefit with perceived value, such as points of some sort?