Michael Herman of Christianity Today just sent in this data on his paid Google text ads using the new system where they are distributed against supposedly relevant content on content sites.
"Both of my Google AdWords accounts are getting a fair amount of impressions in the new third party program, but that's about it.
My first account has had 73,550 impressions and only 462 click-throughs for a wimpy 0.63% click-through rate.
My second account is even worse. 90,159 impressions and only 242 click-throughs for a microscopic 0.26% click-through rate.
I'll take the free clicks, but I don't plan on participating in the program once they start charging. My regular accounts for those same keywords and campaigns are seeing 1.5% and 1.6% click-through rates."
Why such a difference in performance? Well people using search engines are actively looking for links to click on. People on content sites may or may not be.
UPDATE: Ed Kohler of Haystack in a Needle wrote in, "I thought it might be worth clarifying that Google doesn't use or plan to use the click through rates from syndicating when determining the CTR for competition, pricing, etc. So someone like Michael Herman shouldn't consider click through rate when determining whether or not to syndicate. A better focus in on the quality of that traffic." Good point.
BTW: If you're interested, here are links to my Case Study on how Christianity Today makes money online as a free content site, and another Case Study on how its sister-site PreachingToday sells subscriptions.