NEW YORK: The president of the Interactive Advertising Bureau (IAB) has invited Mozilla and other browser companies to work with the trade body to resolve an ongoing dispute about the use of third-party cookies.

In a lengthy blogpost, Randall Rothenburg criticised Mozilla's decision to block by default third-party cookies, which enable advertisers to track online users' visits to the websites on which they advertise.

"Were they to be embargoed tomorrow, billions of dollars in internet advertising and hundreds of thousands of jobs dependent on it would disappear," Rothenburg argued.

He said that while Mozilla's views in this regard were seemingly benign, they ran counter to history. "The entire marketing-media ecosystem has subsisted on purchase-behaviour data and other forms of research being available without individuals' consent," he said, from census data to automotive ownership data.

Rothenburg added that while Mozilla claimed to be defending openness and diversity on the internet, its actions would have the opposite effect as third-party cookies were the technology that made small publishers economically viable.

"Their elimination will concentrate ad revenues in a shrinking group of giant media and technology companies," he declared.

In the blogpost, Rothenburg did not address the issue of users deleting third party cookies themselves. An article in the latest issue of the Journal of Advertising Research highlights the fact that first-party cookies were deleted from an average of 28.5% of computers in a month while third-party cookies were deleted by 32.5% of computers.

The rate of deletion was higher for ad-server cookies (average of nine times per month) than for website cookies (five times per month).

The authors of this research pointed out that this resulted in an over-statement of the true number of unique website visitors and an over-delivery of advertising frequency and a corresponding under-delivery of reach.

Further cookie-related problems included the same person using multiple devices and different people using the same computer.

In the context of arguments about privacy, Jonathan Salem Baskin recently pointed out in Advertising Age that marketers tended to shy away from discussing the vast amount of data it collected on consumers.

"What happens if consumers figure out how regularly, deeply and expertly we marketers track their behaviours, and in doing so blur the line between convenience and manipulation?" he asked.

Data sourced from IAB, Journal of Advertising Research, Advertising Age; additional content by Warc staff