When someone picks you, your content shows up more often in Top Stories with a "preferred" badge, and the same badge can appear in AI Mode and AI Overviews for that user.
Setup is two lines of HTML. One script tag in the head, one empty div where you want the button. Google renders a localized button and handles the rest. If your CMS blocks external scripts, you can link to google.com/preferences/source?q=yourdomain instead, and that link also works in newsletters and social posts.
One limit worth checking first. Only domains and subdomains qualify. example.com works, blog.example.com works, example.com/blog does not. If your client publishes everything under a subdirectory, this feature does nothing for them until they move the blog.
Now the part that matters. This is not a ranking feature. You cannot optimize your way into it, and no amount of schema or internal linking will help. A real person has to decide, on purpose, that they want more of your content. So the button only pays off if you already have readers who would follow you somewhere else. For most B2B service sites and ecommerce blogs, nobody is opting in. For news publishers and anyone with a returning audience, it protects distribution that AI answers keep taking away.
Treat it like a subscribe button, because that is what it is. Add it to sites with real repeat traffic. Skip it everywhere else and stop pretending it is an SEO task.
I am putting the button on the SmartMetrics blog and will report what the numbers actually show after a month.
