Digital publishers are set to sell the behaviour of their online audiences as the next frontier in advertising, according to a report from the Sydney Morning Herald.

Ninemsn, Fairfax Digital, News Digital Media and Google will begin pushing into the controversial area of behavioural targeting.

Behavioural targeting aims ads at internet users based on pages they view, the search terms they use and personal details handed over when registering for web services.

A major part of the monitoring user page viewing is tracking ‘cookies’, which are picked up and stored by a user’s browser, allowing publishers to group internet users together by interest and then sell them on to advertisers.

Although the user’s identity is not revealed, there are fears of privacy invasion.

There is currently a controversy unfolding in the UK surrounding the use of behavioural tracking by internet service providers.

A company called Phorm has come under fire for a secret trial it conducted with BT, one of the UK’s largest internet service providers, in which it monitored every action of thousands of customers online to enable it to send targeted ads to their computers.

Despite the controversy, the industry estimates that ads for behavioural targeting might take as much as 15% of the $500 million-plus display advertising market.

Ninemsn has been targeting users of its Hotmail and Messenger services by age and sex. The company indicates that by the end of the financial year it will be able to follow those people as they move around the Ninemsn network.

“Well know when a male aged 16 to 34 pops up, say in the Wide World Of Sports, and if we have an advertiser interested in getting to them then we can serve up an ad instantaneously,” Ninemsn’s advertising operations director Dominic Finnegan told SMH.

The Interactive Advertising Bureau is following the lead of its British counterpart and is developing guidelines for advertisers involved in behavioural targeting – among them the condition that users must be told clearly what it is and gaining their consent for its use.