Google has begun testing changes to the way companies are able to track users online.
A new feature in the Chrome browser disables third-party cookies – small files stored on your device to collect analytic data, personalise online ads and monitor browsing.
It will initially be available to 1% of global users, about 30 million people.
Google describes the changes as a test, with plans for a full rollout to eliminate cookies later this year.
However, some advertisers say they will suffer as a result.
Google’s Chrome is the world’s most popular internet browser.
Rivals such as Apple’s Safari and Mozilla Firefox – which account for far less internet traffic – already include options to block third-party cookies.
Google says randomly-chosen users will be asked if they want to “browse with more privacy”.
Anthony Chavez, Google vice president, said in a blog post: “We’re taking a responsible approach to phasing out third-party cookies in Chrome.
“If a site doesn’t work without third-party cookies and Chrome notices you’re having issues… we’ll prompt you with an option to temporarily re-enable third-party cookies for that website.”
Google says it is working to make the internet more private.
But from the point of view of many websites, cookies are a vital part of selling the advertising on which they depend.
For some that advertising can feel intrusive.
Many people will have the experience of visiting a website, or making a purchase and then having related ads appear on all the sites they visit.
Cookies can be used to record various kinds of data about users including:
• what you do on the site
• whereabouts in the world you are
• what device you are using
• where you go online afterwards
“Google’s solution, the Chrome Privacy Sandbox, which only works on a Chrome browser, likely doesn’t benefit anyone other than Google,” said Phil Duffield, UK vice president at The Trade Desk, which operates a platform for companies to buy ads online.
“Protecting consumer privacy online, doesn’t have to mean making it harder for publishers to earn revenue”.
He added “the advertising industry is on a collective mission to build something better”.
The UK’s competition watchdog, the Competition and Markets Authority, can block the plans if it concludes they will harm other businesses.
BBC
