Ep 3: Lazy loading ads without losing impressions

Myth. Lazy loading your ads throws impressions away.

Lazy loading means an ad is requested only when its slot gets close to the screen.

On news.example, an article has five ad slots. Without lazy loading, all five load at once. Say half your readers never reach slot five. That ad loads anyway, unseen, slowing the page and hurting viewability. With lazy loading in the Google Publisher Tag, you set two margins. Fetch the ad one screen away. Render it at half a screen. You mostly drop impressions nobody would see. The real risk is a margin that’s too tight. If your auction takes one second and a reader scrolls past faster, the slot arrives empty. That impression really is lost. Phones scroll faster, so widen the margins there.

Compare viewable impressions per page view before and after. If they fall, widen the fetch margin.

Next, ad refresh, time-based versus viewable.