Yahoo, one of the first large Web companies to recognize the Do Not Track header from browsers on its properties, has now backtracked and said it will no longer support DNT.

Yahoo, one of the first large Web companies to recognize the Do Not Track header from browsers on its properties, has now backtracked and said it will no longer support DNT. Officials said the lack of an industry standard for DNT that’s effective led to the decision.

DNT is an option in the major browsers that allows users to tell sites that they don’t want their activities tracked as they move around the Web. In practice, browsers send a header to sites expressing the user’s DNT preference. Sites can either respect or ignore that header, and Yahoo’s sites from now on will ignore it.

“As of today, web browser Do Not Track settings will no longer be enabled on Yahoo. As the first major tech company to implement Do Not Track, we’ve been at the heart of conversations surrounding how to develop the most user-friendly standard. However, we have yet to see a single standard emerge that is effective, easy to use and has been adopted by the broader tech industry,” Yahoo officials said in an unsigned post on Thursday.

There has been a lot of discussion in the security and privacy community about the usefulness of DNT as a privacy technology.

There has been a lot of discussion in the security and privacy community about the usefulness of DNT as a privacy technology. The argument against DNT mainly relies on the fact that users don’t actually have any control over whether sites track them, thanks to the system’s reliance on sites to respect the header. If a site chooses not to respect the DNT header, all bets are off. And users have little, if any, visibility into whether a given site will respect the header.

Meanwhile, the EFF, one of the main proponents of the DNT system, is working on a new browser add-on called Privacy Badger, which is designed to prevent tracking from advertisers and others around the Web.

“Privacy Badger is a browser-add on tool that analyzes sites to detect and disallow content that tracks you in an objectionable, non-consensual manner. When you visit websites, your copy of Privacy Badger keeps note of the “third-party” domains that embed images, scripts and advertising in the pages you visit,” the EFF said in a post introducing the extension.

“If a third-party server appears to be tracking you without permission, by using uniquely identifying cookies to collect a record of the pages you visit across multiple sites, Privacy Badger will automatically disallow content from that third-party tracker. In some cases a third-party domain provides some important aspect of a page’s functionality, such as embedded maps, images, or fonts. In those cases, Privacy Badger will allow connections to the third party but will screen out its tracking cookies.”

Privacy Badger is available as an alpha release for both Mozilla Firefox and Google Chrome.