Google treats intrusive interstitials, overlays that make content hard to reach, particularly on mobile, as a negative signal.
Problematic
- A popup covering the main content immediately on arrival from search.
- A standalone interstitial the user must dismiss before reading anything.
- A layout where the above-the-fold area is an ad and the content is pushed below.
Acceptable
- Legally required notices, cookie consent, age verification.
- Login walls for genuinely private content.
- A modest banner that uses a reasonable portion of the screen.
Alien Road recommends: delay any marketing overlay until the visitor has shown intent, scroll depth or time on page, and never fire it on the first paint from a search click. This protects the signal and, in every test we have run, converts better than an immediate popup because it interrupts a reader instead of a stranger.