The majority of our business growth is word of mouth. It's the best form of advertising as not only is it free, but it's coming from a trusted source. Offering an affiliate program helps, but we have a number of people that post in blogs, send friends and business clients to our service and expect nothing in return other than continued good service.
When I do recomendations of things myself I prefer not to be on an affiliate program as then the review is MY view, and not just something I'm pushing on clients so I can make a buck. I also don't advertise anything on my websites that I have not or do not personally use. It's why we don't have a page listing design companies offering affiliate and payouts