Privacy Badger is a browser extension, created by the EFF, that blocks third-party non-consensual trackers. Third-party trackers are those that are included on websites that you visit (first party), and by large, are invisible to the end user.
Many privacy focused browser extensions contain features that purport to block trackers -- but largely, for most people, a standalone extension such as Privacy Badger is a more effective choice, especially if these extensions are running with default settings.
One very prominent third-party tracker that we're all familiar with is Facebook. Many sites have 'Like on Facebook' widgets embedded within their content. Most users are unaware that these widgets track user behavior across the internet.
The settings panel for Privacy Badger is quite simple. You've got a list of domains and a toggle button with three colors:
By default, Privacy Badger will send Do Not Track headers to websites that you visit. This is an essential part of the functionality of the extension -- which is a shame, because Do Not Track can often lead to you being more susceptible to browser fingerprinting.
According to the EFF, if a website or service makes a commitment to respect the Do Not Track standard, their cookies will be unblocked.
This creates some complexity, as DNT as a standard has been fraught with setbacks and mostly abandoned in recent months. For example, very few advertisers support the standard (Google and Microsoft famously do not), so a question arises: is the signal too noisy to be actionable? The long-term viability of Do Not Track seems pretty shaky, and having it as a core heuristic might spell certain disaster for the extension.
Most anti-tracking plugins, including those that block ads, work off of a blacklist. When a new tracker is added to the blacklist, all of the users who have the extension installed receive an update, and the tracker is blocked for everyone at once.
Privacy Badger doesn't work this way, but rather, is based on something called heuristic blocking. The way that Privacy Badger works is that every installation begins as a fresh slate. As you browse the web, the embedded algorithm looks for trackers that track you across three or more sites. This methodology means that it becomes more effective the longer you use it. Note that if you want Privacy Badger to learn while in incognito mode, you'll have to toggle the setting.
Perceptive readers will see a significant distinction here. Privacy Badger seeks to block third-party trackers and is almost entirely agnostic of what first-party sites do. This is a major philosophical stance -- Privacy Badger is behavior focused, as opposed to blacklist focused.
By default, every link that you click on Facebook, Google, or Twitter, has tracking parameters appended onto it. It's one of the core ways in which these companies learn more about their users. One advantage over other anti-tracking extensions is that Privacy Badger cleans links from Facebook, Google, and Twitter. Most others do not.
Any browser-based anti-tracking extension runs the risk of breaking some websites that you visit. In the three or so weeks that I ran the extension, I noticed only two or three sites that had degraded functionality.
Privacy Badger is a browser extension, so it is operating system agnostic.
The desktop browsers currently supported are Google Chrome, Mozilla Firefox, and Opera.
Privacy Badger also supports Firefox on Android mobile devices.