"Viewability" is an ad industry metric of "did your ad actually appear on screen, or was it below the fold?" It's actually pretty hard to detect except through

"Viewability" is an ad industry metric of "did your ad actually appear on screen, or was it below the fold?" It's actually pretty hard to detect except through indirect means, one of which was to use a flash object to monitor for framerate changes. On-screen objects would render with a higher framerate. Google seems to have built out an API so that you can just explicitly check. For marketers, this is actually a big thing because it means a key success metric (did people actually see your ad?) can be measured more reliably. You can disdain advertising or marketing in general and you'd have a point, but what you quoted is actually describing a well thought out solution to a common industry problem.