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Which Extension Protects Better?

What is this?

AreWePrivateYet recreates Stanford University's Tracking the Trackers: Self-Help Tools study on a continuous basis in a reproducible way. The above chart compares the level of protection provided by the different privacy extensions across various metrics.

Does higher mean better?

AreWePrivateYet charts percentage decreases from the default Firefox profile (baseline) across all metrics. Higher bars mean fewer requests/less storage, which we take to mean less tracking.

How is this chart produced?

We maintain several servers that execute monthly Selenium-driven Firefox crawls of the homepages of 1,000 popular websites.

Each crawl is conducted with a fresh Firefox profile configured to use the latest version of a particular privacy extension. Third-party Cookie Blocking and DNT crawls do not use an extension but rather set Firefox to block all third-party cookies and send the Do Not Track header, respectively. Finally, a no-extension, all-defaults crawl is performed to establish a baseline.

During a crawl, a customized Fourth Party extension collects all request metrics, storing them in a database for later analysis by AreWePrivateYet scripts, which produce the data for the above chart.

Metrics used

AreWePrivateYet uses the following metrics:

* third-party metric

Extensions used

We chose the most popular privacy extensions that feature some sort of tracker blocking functionality.

Extension Blocking Settings
Adblock Plus (EasyList) Subscribed to EasyList.
Adblock Plus (Fanboy)1 Subscribed to Fanboy Adblock List.
Adblock Plus (Suggested Lists) Subscribed to Fanboy's Social, EasyList, Malware Domains, EasyPrivacy.
"Acceptable Ads" enabled.
Adblock Edge (Suggested Lists) Subscribed to Fanboy's Social, EasyList, Malware Domains, EasyPrivacy.
Disconnect Default settings.
DoNotTrackMe "Abine suggestions" disabled.
DNT Header Not an extension: A blank Firefox profile with Do Not Track enabled.
Ghostery All trackers blocked.
Third-party Cookie Blocking Not an extension: A blank Firefox profile configured to block third-party cookies.
TrackerBlock Default settings.

1. Fanboy's list has been merged into EasyList. July 2013 is the last available report for this ABP configuration.

What about NoScript and RequestPolicy?

Both NoScript and RequestPolicy require extensive, per-site configuration for a usable Web experience. Since there is no single representative set of settings for either extension, including NoScript or RequestPolicy would be similar to performing a crawl while disconnected from the Internet.

I want to see what's under the hood

The source of the project is hosted on GitHub.

I have another question

Please e-mail areweprivateyet@ghostery.com.