<b>Lazy-Load rootMargin: The 200px vs 600px Argument</b>

<b>Lazy-Load rootMargin: The 200px vs 600px Argument</b>

Everyone lazy-loads ads now. The lever nobody tunes is the IntersectionObserver rootMargin — how far ahead of the viewport you trigger the request.

What it does — controls how early below-fold ads start loading as the user scrolls.
Setup effort (2/5) — one config value if your stack exposes it (GPT lazy load, Ezoic, AdThrive all do).
RPM lift seen — moving from a tight 0px to ~300px lifted viewability-adjusted RPM +8% by cutting unfilled-on-scroll-past impressions; going to 600px+ erased the gain (loads ads users never reach).

Pros — fixes the 'ad loads after I've scrolled past' viewability tax.
Cons — too generous and you reload data + hurt fill on fast scrollers.

Lift: ★★★★☆ — Risk: ★★☆☆☆
Best for: mobile long-scroll. Skip the tuning if sessions are single-screen.