LONDON: Brands and online advertisers have been warned to exercise caution about how they use consumer data or risk prescriptive legislation from policymakers seeking to address concerns about privacy.

Speaking at an event organised by online privacy consultants TRUSTe, online ad practitioners were told it was their responsibility to be more transparent and to explain themselves better to legislators, Marketing Week reported.

Nick Stringer, head of regulatory affairs at IAB UK, the industry body for digital advertising, said: "The role of our business models is not well understood and it's up to us to show how they work and show the economic value of these [online behavioural advertising] business models."

Although he accepted that the industry had taken steps to improve consumer education and that the UK authorities supported the sector, as did elements within the European Commission, more work needed to be done.

Separately, Dave Deasey, VP of marketing at TRUSTe, presented recent research that showed privacy was a top concern for 20% of mobile consumers and second only to concerns about battery life.

The study also found 37% of respondents checked if an app had a clear privacy policy before they divulged personal information.

Wednesday's event took place on the same day that Facebook announced changes to its privacy policy, allowing teenagers aged 13 to 17 to share their posts with anyone on the internet, Associated Press reported.

Facebook has introduced protective measures, such as an automatic caution before every public post, but the move has stirred unease.

Kathryn Montgomery, professor of communication at the American University in Washington, warned that teenagers had a tendency to take risks and often don't understand the consequences of their behaviour.

"What this is really about is maximising the kind of sharing at the heart of Facebook's business model," she said, adding that to allow teens to share more about themselves will enable advertisers to collect more personal data about minors, who would be unaware that their "interests are under a digital microscope".

Data sourced from Marketing Week, Associated Press; additional content by Warc staff