http://www.theonestopwebsiteshop.com/onlin...ted-traffic.htm
Just found it looking around on google.
I'm not so sharp though, I don't understand your argument.
Say you have a stockbroking business (which is nowhere in the search-engines) and I get my site up in the top 10 of google which basically promotes your site, then is that traffic not worth buying on a CPC basis? It's certainly targeted because they've found my site most probably under the term 'stockbroker' etc.