Yes, this is so true. Highly targeted traffic is what clickbank needs. I have a site dedicated to one clickbank product only, receiving 25 visitors a day max, 5 hops and 1 sale, which I think is good enough considering I don't do SEO at all.
I setup my new site with an initial 10 keywords, leave it for 15 days with getclicky installed. After that, I scrub the generated keywords used to find my site and write articles for them. I keep my site/blog alive by adding 1-2 articles every 2 weeks or so.
Also, Seo Rank Reporter (a wordpress plugin) also generates the keywords used to find my site. Not as good as getclicky but also helps me find the right longtail keywords to target for my next article.