The company said that the lack of a "single standard" on DNT was a factor behind its decision, but sought to reassure web users that they would still be able to exercise controls over privacy when using Yahoo! services.
"As of today, web browser 'do not track' settings will no longer be enabled on Yahoo," a blog by the privacy team at Yahoo! said. "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."
"Users can still manage their privacy on Yahoo while benefiting from a personalised web experience. We encourage our users to tailor their online experience through the variety of privacy tools we offer within our own platform ... The privacy of our users is and will continue to be a top priority for us."
In 2011 the body responsible for ensuring that web technology is based on an agreed set of technical standards, the World Wide Web Consortium (W3C), published plans to create a universal 'do not track' mechanism in web browsers that would give users control of their privacy settings across all sites.
Since then a number of stakeholders, from advertisers, web browser manufacturers and other internet and technology companies have been involved in ongoing efforts to develop a new DNT standard. However, to date no such single standard has been agreed on.
Last year the Digital Advertising Alliance (DAA) put forward plans to exempt targeted advertising from being subject to the new standard being developed. The DAA had proposed that internet users would be able to control the targeted advertising they received through its own, separate, "opt-out mechanism". However, those plans were rejected by the Tracking Protection Working Group overseeing the development of the DNT standard within the W3C.
Yahoo! previously announced in October 2012 that it would not recognise settings Microsoft at the time had indicated that it would automatically set within a version of its Internet Explorer browser which would block targeted adverts unless users altered those settings to opt in.
The European Commission has previously admitted that adherence to the DNT standards being developed by the W3C would not, on their own, allow website operators to comply with EU rules on 'cookies'.