Sites that require some kind of age verification gating system, such as you see on alcohol sites or some video game sites, can be a complicated thing when it comes to SEO. On the one hand, those sites are required by law to ask someone’s age before viewing the content on the site. But on the other hand, those sites still want to have a footprint in Google, especially so people can find the content on those sites when they do a search.
Using an interstitial is the standard method for sites, but that method has become a bit more complicated with Google’s change to interstitials and popups that sees Google demote content in the search results that use interstitials or annoying popups.
John Mueller from Google was asked about the best method for using an age verification gate, and he suggested that instead of the usual interstitials, that popup-style DIVs are a better solution in this case.
These are always tricky. Popup-style DIVs are usually better than interstitials; avoid redirects to interstitials.
— John ☆.o(≧▽≦)o.☆ (@JohnMu) June 7, 2017
Google has said previously that their interstital demotion wouldn’t impact sites requiring age verification, however, there is the possibility that is because all sites in that market area abide by the same age verification rules.
