The heat maps of eye movement were fascinating...I noticed the almost complete lack of activity on the advertisements immediately. Users appear to do what I do, just simply ignore them or try and filter them out.
In Mac OS X i guess Apple caved to popular convention and moved the scroll bars to the right.
People also ignore anything in colored blocks, or that looks like an ad.
Thus ReCaptcha had a huge problem initially with people just "not seeing" it on the forms where it was placed. It looked like an ad.
It appears that people unconsciously set an "attention getting threshold", things that are designed to attract attention go above that threshold and are simply ignored. This seems to be well known hence the various forms of pop-up and pop-over ads that are showing up on sites again now even though they were proven to annoy users to the point of having to derive engineering solutions to the problem.