My local newspaper has a horrible website. Things move around continually as the page renders, and it is very easy to accidentally click an ad. I'm sure that isn't an accident.
I doubt Google and Facebook are any better but the catch and the question is; how to measure awareness of ads e.g. if I see an ad and it sticks in my mind but that doesn't show up in advertiser's ad campaign analytics? Raw stats are one thing but awareness is another.