I've tried ClickBank for Adwords only once or twice and it didn't work out for me. I always feel it's a big risk trying to promote an ebook and then buying ads on the topic. Here's what I mean:
When people are searching for information, are they really looking to buy an ebook? I don't think so. For my AdWords campaigns I have stuck with tangible products that people are searching for and have had a much better result.
As a search engine user, if I search for "dog blanket" (just an example)...I likely want to buy a "dog blanket". But if I search for "how to build a website"...I want information, I don't necessarily want to buy an ebook.
Won't your conversion rate be much lower on the ebook? I guess the commissions are often higher, so it may be worth that risk. Maybe, I'm just a chicken. I'm really interested to hear from others who have had good conversions from promoting ebooks.
Alice