I've got a theory. I think that most people feel uncomfortable taking money from someone else where there has not been a fair value exchange.

Note, fair value exchange.

Affiliate or referral programs are most commonly used to incentivise and encourage existing members of an organisation to bring in new, fee paying, members. The more you bring in, the more money you make. So what's the difference in social networks? Well, let's say I introduce you to a networking website (ecademy, SoFlow & OpenBC are good examples) where for a certain level of membership there is a fee. You decide to join up and pay the fee, fair enough. Now, would you feel any differently if you knew that 10% of what you've just paid is going in my pocket. Maybe you would, maybe not. My theory is that you would and it's based on the fact that you won't feel that you've got value for your 10% "simply" through me mentioning the name of a website to you. That's one side of the story. The other side is how do I feel about taking the 10%. Of course there will be many who are always happy to take money, from anyone, regardless of circumstance. Let's cast those aside. My personal view is that if I have mentioned a website to you I am not expecting any kind of compensation for that - whatever the method. Whilst there may be value in me introducing you to the site, it's not something I would either want or expect to make money on. It's analogous to helping someone in the street who wants directions. Just before you give them the final turn in the directions you interject with "That'll be a tenner please"! (I must try that ;) Now to throw in a final dimension. In the absence of any referral program I would introduce you to a particular site for a particular reason. One has to wonder how some are influenced if they know there is money in it for them. Would you favour one, of two similar sites, it you were an affiliate of it?

So this is my theory, affiliate programs can't work in social networks. This said though, in the words of the actor Matt LeBlanc in his character Joey from Friends, "...a lot of theories didn't pan out. The lone gunman. Communism. Geometry..."