Refback

A refback is one of four types of linkbacks, methods for Web authors to request notification when somebody links to one of their documents. This enables authors to keep track of who is linking to, or referring to their articles.

A Refback is simply the usage of the HTTP referrer header to discover incoming links. Whenever a browser traverses an incoming link from Site A (originator) to Site B (receptor) the browser will send a referrer value indicating the URL from where the user came. Site B might publish a link to Site A after visiting Site A and extracting relevant information from Site A such as the title, meta information, the link text, and so on.