Banner blindness: the inability of users to see ads right in front of their face.
This problem sometimes gets passed off as a problem with layout.
If you just put the ad where users expect to find navigational links or content, some people argue, you’re going to see a boost in click through rate.
I’m not going to claim that this approach has never worked or that it can’t work in some situations.
In fact, I’ll go ahead and say that when it comes to layout, the science suggests the best place to put an ad is at the top of a page.