SAN FRANCISCO • Google is weaning itself off user-tracking "cookies" that allow the Internet giant to deliver personalised ads but which have raised the hackles of privacy defenders.
Last month, it unveiled the results of tests showing an alternative to the longstanding tracking practice, claiming it could improve online privacy and still enable advertisers to serve up relevant messages.
"This approach effectively hides individuals 'in the crowd' and uses on-device processing to keep a person's Web history private on the browser," Google product manager Chetna Bindra explained in unveiling the system called Federated Learning of Cohorts (FLoC).
"Results indicate that when it comes to generating interest-based audiences, FLoC can provide an effective replacement signal for third-party cookies."
Google plans to begin testing the FLoC approach with advertisers this year with its Chrome browser. "Advertising is essential to keeping the Web open for everyone, but the Web ecosystem is at risk if privacy practices do not keep up with changing expectations," Ms Bindra said.
Google has plenty of incentive for the change. It has been hammered by critics over user privacy, and growing fear of cookie-tracking has prompted support for Internet rights legislation.
Some kinds of cookies - text files stored when a user visits a website - are a convenience for logins at frequently visited sites. Anyone who has pulled up a registration page online and had their name and address automatically entered where required has cookies to thank.
But other kinds of cookies are seen by some as nefarious.
"Third-party cookies are a privacy nightmare," Electronic Frontier Foundation technologist Bennett Cyphers said. "You don't need to know what everyone has ever done just to serve them an ad."
Browsers Safari and Firefox have done away with third-party cookies, but Chrome, the world's most popular browser, still uses them. Chrome accounted for 63 per cent of the global browser market last year.
Mr Cyphers and others have worries about Google using a secret formula to lump Internet users into groups and give them "cohort" badges of sorts that will be used to target marketing messages without knowing exactly who they are.
"There is a machine learning black box that is going to take in every bit of everything you have ever done in your browser and spit out a label that says you are this kind of person. Advertisers are going to decode what those labels mean," Mr Cyphers said.
Business coalition Marketers for an Open Web is campaigning against Google's cohort move, questioning its effectiveness and arguing that it will force more advertisers into its "walled garden".
"Google's proposals are bad for independent media owners, bad for independent advertising technology and bad for marketers," said coalition director James Rosewell.