Dropbox is a good case in point. I use their service, and happily refer my friends to it-- the "affiliate fee" from Dropbox, in the form of extra storage) is a

Dropbox is a good case in point. I use their service, and happily refer my friends to it-- the "affiliate fee" from Dropbox, in the form of extra storage) is a nice bonus. If my friends refer their friends, that's none of my concern-- and if Dropbox made it my concern (via some incentive), that would feel very uncomfortable for me. I don't want to be that involved in Dropbox's business, and I don't want to start thinking about who I can refer that can refer a lot of other people, or how I can push my friends to refer others, etc. Similarly, if I have some books I want to recommend on a blog, I have no problem using an Amazon affiliate link. For me to put up a link trying to sign up more affiliates for Amazon, on the other hand, feels wrong-- I've crossed the line from "recommending" to "shilling." I'm not saying that it is impossible to do multi-tier affiliate systems well; I'm sure there are people that are doing it properly, somewhere. But I'd certainly not make a blanket recommendation that everyone should attempt it, or even that it is appropriate in the majority of cases.