Online tracking: A 1-million-site measurement and analysis is the largest and most detailed measurement of online tracking to date. We measure stateful (cookie-based) and stateless (fingerprinting-based) tracking, the effect of browser privacy tools, and "cookie syncing".
This measurement is made possible by our web measurement tool OpenWPM, a mature platform that enables fully automated web crawls using a full-fledged and instrumented browser.
In a crawl conducted during January 2016, these websites were found to run scripts on their homepages which use WebRTC to recover a user's local IP address. The scripts are labeled as tracking scripts, non-tracking scripts, and those for which the use is not clear.