Privacy Badger, an open-source Chrome and Firefox extension designed to protect users against third-party tracking, has been launched in alpha by the Electronic Frontier Foundation (EFF), a digital rights group.

The plugin monitors tracker behaviour to determine which are likely to be collecting user data without consent, a method that differs from the blacklisting used by similar extensions such as AdBlock Plus, the code of which forms the basis for Privacy Badger.

Trackers are automatically classified using a red/amber/green system, allowing users to moderate each one separately, with the amber setting authorising cookies necessary for website functionality and blocking those seeking user data.

A whitelist for companies that comply with the Do Not Track protocol, a browser setting which tells websites the user does not want their data collected, is incorporated into the extension.

"Privacy Badger is EFF’s answer to intrusive and objectionable practices in the online advertising industry, and many advertisers’ outright refusal to meaningfully honour Do Not Track requests," the foundation said.

The EFF was responsible for drawing attention to online "fingerprinting", a process in which websites can track unique users based on their browser settings. The foundation hopes to guard against this in a future update of Privacy Badger, and its project Panopticlick allows users to assess their risk.

"This is an alpha release; we’ve been using it internally and don’t think it’s too buggy. But we’re looking for intrepid users to try it out and let us know before we encourage millions of people to install it."

The release comes just days after Yahoo announced it would abandon the Do Not Track protocol, claiming that it was antithetical to "a personalised experience" on the web. The company joined Google and Facebook in their refusal to comply, despite Microsoft automatically enabling the setting by default on its Internet Explorer browser.

In addition to developing extensions to protect privacy, EFF have engaged in a number of court battles in the United States, as well as writing white papers on the state of digital rights.