If you're talking about the website in your signature, then I'll tell you this: There's only one ad I can see on the homepage, it's above the fold which is good, but a lot of people ignore things in the header if they're looking for content. I'd definitely leave it there, but think about adding some text ads or blocks down the side, between posts - just don't make it intrusive. It also depends on your niche and how relative the advertisements are to the content; people are more inclined to click advertisements that relate to whatever they're reading or looking for.
It can be due to one of the below reason 1. Low quality site 2. bad design / layout 3. Low quality traffic / non-targeted traffic 4. Bad ads placement / setting
how many visits are you getting, I can see you only have 1 horizontal ad in the header. from my experience, ctr depends on ad placement. Check my blog to know more http://www.binarytides.com/increase-adsense-ctr-using-larger-ad-units/
I was just about to say the same thing. Usually the blogosphere/webmasters would be more interested in tools/ebooks on marketing and the like.