Case: vignette interstitial vs anchor unit, head to head

Case: vignette interstitial vs anchor unit, head to head

What it did: A/B'd Google's vignette interstitial (between pageviews) against a persistent bottom anchor on the same mobile section.

— Setup effort: 2/5 (both are GAM toggles)
— Outcome: interstitial earned +$1.80 RPM but bounce rose 4.2% and pages/session fell 0.6; anchor earned +$1.10 RPM with bounce flat
— Net session RPM: anchor variant actually won by 7% once you account for lost pageviews

Pros of measuring this way: headline RPM lied — the interstitial "won" per page but lost per session.
Cons: interstitials still help on single-page, high-bounce traffic.

Lift (anchor): ★★★★☆ — Risk: ★★☆☆☆
Verdict: prefer the anchor for multi-page sites; reserve interstitials for one-and-done traffic. Best for: anyone choosing between the two. Skip blind interstitials on sticky audiences.