|Jan 22, 2019||»||Tracking and Data Collection
4 min; updated Feb 12, 2023
Tracking on the Internet Screenshot from a [2012 study of third-party online tracking](#mayerMitchellThirdPartyWebTracking). The red boxes show content (at least the visible ones) served by third parties. When the browser requests a third-party resource embedded on a web page, the snippet below is a subset of the HTTP headers sent by the browser to the third party. GET http://youtube.com/watch?v=gHStnhGx1P Cookie: id=35c192bcfe0000b1... Referer: http://www.nytimes.com/ The combination of the cookie and the referrer makes third-party tracking possible....