Any time a visitor comes to your site, chances are they came from somewhere else. The site that they come from, therefore, is called the referring site. This report shows you the domain name or IP address that referred a visitor to your site, in descending order, based on the number of times that domain name or IP address was the referrer.
Note: You will often see a "No Referrer" listed. This can happen if a visitor navigates to a URL by typing it into the browser's address bar or if the website is set as the browser's homepage. In addition, there are also some scripts and privacy programs that can be used to block referral information when a visitor navigates from one website to another.