Ad blockers can do what you suggest, but it's very rudamentary. What it relies on, almost exclusively, is blocking calls to known ad networks. In my experience,

Ad blockers can do what you suggest, but it's very rudamentary. What it relies on, almost exclusively, is blocking calls to known ad networks. In my experience, about 95% of ads are blocked this way. Even if it was only 50%, that's still a gigantic number of previously unseen ads being seen.