Search engine joins Google and Facebook in noncompliance with consumer requests.
Yahoo has abandoned the Do Not Track (DNT) standard, and will now track users irrespective of their browser settings, according to a blog posted on the company's tumblr.
DNT is activated through the settings of the web browser, using the HTTP protocol to signal to websites that the user does not wanted to be tracked. However, there is no obligation for companies to honour the request, despite lobbying from a number of privacy groups.
A statement from the Yahoo Privacy Team 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."
Attempts to legislate the standard in the US have so far failed, following resistance from advertisers and tech firms who could lose billions of dollars as a result, who argued it may damage the viability of ad-funded websites, and even "kill free speech".
Microsoft previously caused a stir when it announced it was enabling DNT by default in September 2012, in contrast to Google and Facebook's refusal to comply with the standard last year. The issue has deeply divided the industry, with companies lining up on either side.
Speaking to Forbes about consumer privacy, Mozilla's chief privacy officer Alex Fowler said: "We are seeing an incredible expenditure of money and talent to refine the tracking ecosystems and we are not seeing the same comparable investment in controls that are meaningful to the user."
Source: Company Press Release