Which Chrome API or other Google API is Pinterest exploiting here to detect visitor email addresses?
"Use pinterest.com with Google"
Which Chrome API or other Google API is Pinterest exploiting here to detect visitor email addresses?
"Use pinterest.com with Google"
I believe this is Google Identities "One-tap sign-up" feature.
With Google's one tap sign-up and automatic sign-in APIs, new users can sign up to your site with just one tap on a dialog that's inline with your page's content. Returning users are signed in automatically, even when they switch devices or platforms, or after their session expires. - Google Identity case studies
It seems that this is currently a beta API feature which they are currently improving cross-browser functionality.