The page URL that originally generated the request for the current page view, as indicated by a server's referrer log file. An internal referrer is a link on another page within the Web site. An external referrer is on a page outside the Web site. A search referrer is a link generated in a search function whether internal within the Web or from an external search engine.

If a visitor comes directly from a search engine listing, the query used to find the page will usually be encoded in the referrer URL, making it possible to see which keywords are bringing in visitors.