Changes to the tokens that underpin digital advertising's ecosystem could have deep ramifications for marketing strategies - and for the platforms that execute on behalf of brands and agencies. But it hinges on whether people actually choose to block cookies - an unknown until Google implements its changes.

Google’s stated motives around data privacy have been met with scepticism, especially from ad tech companies that will suffer as a result of cookie changes. 

There’s also the question of timing. As political pressure builds for lawmakers to rein in the titans of the surveillance economy, taking steps to head off regulatory intervention makes sound business sense.

Yet Chrome is the world’s biggest browser, allied to the world’s biggest search engine and ad business. On past performance, Google is highly unlikely to do anything that hobbles its cash cow.

For the broader ad industry, cookie cutting could be transformational. For some, potentially terminal, which might just result in more money for Google. With users largely logged in - and opted in - for all the personalisation they can eat in return for free services, Google has less dependence on the code that underpins the business models of some of its competitors. Removing rivals' ability to create workarounds with fingerprinting compounds their looming problems.

A cynic may suggest that when it comes to privacy pivots and walled gardens, anything Facebook can do, Google can do better. Proponents argue that if it prevents the ad industry exploiting loopholes and stops people being chased around the internet by a pair of shoes they bought three weeks ago, there may yet be some upside. But parts of the digital ad industry are bracing for the worst: Omnicom Media Group CEO Scott Hagedorn believes the move "renders DMPs almost useless". He fears 80% of cookies will be wiped out.

Others believe the move will drive advertisers and publishers to create more premium private marketplaces or publisher alliances weighted towards first party data.

Either way, third party cookies have been on notice for the best part of a decade. Now the advertising industry and publishers have even greater impetus to collaborate on solutions.