I don't think this is true, I run an affiliate site that directs people to Smile, and my commissions have been the same whether I direct to Smile or not. I have heard that your conversions typically go down when you use Smile. However I think that might be because many customers have never signed up for Smile and are scared away. I decided to stick with Smile links because I thought that in the long term it would motivate people to continue using my site and I figured at worst I'd help charities a lot more than the income I'd lose so I'm a bit sad to learn about this.