Suppression of the Referer Header

Requests with a Missing or Incorrect Referer Header (283,945 observations). The x and y represent the domain names of two web servers.

Requests with a Missing or Incorrect Referer Header on Ad Network A (241,483 observations). Opera blocks cross-site document.referrer for HTTPS. Firefox 1.0 and 1.5 do not send Referer for XMLHttpRequest due to a bug. The PlayStation 3 (denoted PS) does not support document.referrer.