A feature on Facebook Ads which allows the Facebook Pixel to scan webpages it is on to glean more information about the user of the website (such as information filled in on forms on the website).
Facebook Ads will then add this information to the profile they hold about that person so they can more effectively target ads at them. This feature is part of Facebook’s “Power5” and was called “Auto Advanced Matching” in there.
I would not recommend that websites turn it on, as it feels incredibly invasive.
Glossary Index