I think all the sites that condone rakeback should offer the service themselves. What do they need affiliates for? All the signups for rakeback is done by word of mouth. All the site has to do is post in a few forums the percentage of rakeback they are offering or just post it in on their website. If they want to do it more discreetly, they can make it known on the major forums that if an email request is sent to the marketing dept, they will get rakeback. For all other players who are clueless about the rake and do not make that request, they will get no rakeback. It is also better for the poker site to do it themselves because they do not have to worry about rogue rakeback affiliates not paying their players.
Go to the major rakeback sites and you will notice that they do not provide any information that attracts new players. They do not have pokerroom reviews, poker rules, poker strategy, or anything else that new players are seeking. They are just a bunch of parasites looking to steal existing players. A rakeback affiliate does nothing to attract new players, so they should not even be allowed to exist. They are parasites who need to be exterminated as soon as possible.
As the market grows and matures, it will consolidate and those sites who use rakeback now to survive, will not even exist. Rakeback will evaporate, it is only a matter of time.