The English term referrer is also used in German. It is said to be due to a spelling mistake. According to this, the authors wrote Referrer instead of Referer when documenting the Hypertext Transfer Protocol(HTTP).
A referrer is the Internet address of the web page from which another web page is referred to. The Uniform Resource Locator( URL) of the referring web page is transmitted and evaluated in the header of the HTTP protocol. The referrers are stored in the log files and provide information about the origin of the visitors.
Referrer belongs to the environment variables of web servers. It is a part of HTTP query. And its structure corresponds to http://www.verweisende-webseite.de. The knowledge gained from the evaluation of referrers flows into online marketing and is used to check and improve the efficiency of online advertising.