I've used it off and on, but never made anything out of it. I think maybe you need to concentrate on a particular group of products or even only one or two, and then promote the heck out of your site. I relied (foolishly) on existing traffic to my existing site and basically got no bites. The people who visit my regular site are readers, not clickers, it seems. I think the potential in clickbank is far greater than that of, say, adsense.