Learn about tracking technologies, market structure and data-sharing on the web

WhoTracksMe Paper 2018

What is a tracker? Where does this data come from?


June Update - Do you consent?

The rushed, rough and rogue UX of services getting you to opt-in.


Tracker Tax

The impact of third-party trackers on website speed in the United States.


May Update - Countdown to GDPR

Facebook's "Tough" month and Google's recommendation

Tracker Market Share

Proportion of the web traffic tracked by these companies.


WhoTracksMe 2018

See Full Chart

Google trackers are present on 82% of the web traffic

That is more than the next 4 biggest trackers combined.

#trackerTopia #growth #topSites

28% of the web has a hidden Facebook tracking pixel

Facebook knows more than what you just do on Facebook

#facebook #trackingPixel #reach

509 companies track more than 0.1% of the web traffic each.

Which of these have you heard of?

#unknown #pervasive #mydata

Websites with the most (and least) tracking



out of 2172 top websites have more than 10 trackers per page.


of data per page load on average required by trackers

FINGERPRINTING is a unique digital signature derived from the properties of your device.

COOKIES are files placed by the website, stored in the browser that is used to identify you to the website.

The most common trackers