What’s it like to have your personal details shared with the world? Kelly Bayer Rosmarin found out last weekend after Australian journalist Liam Mendes tailed the Optus chief executive around during a weekend break.

Under the headline, ‘Short Highlands fling for Optus chief…’ the Murdoch masthead shared details of Rosmarin’s weekend movements, her $4 million property, her husband, her Italian greyhound Vespa and the $40.20 they paid for three tickets to a flower festival in a park near Bowral town centre, one presumably for her bodyguard.

No doubt confusing public interest journalism with “journalism” that might interest the public, Mendes reports that she was “unnoticed by members” of the public.

Less successful in researching her husband, the former photographer continues with details of their Vaucluse home and the cost of their renovations, stopping just short, it seemed, of sharing their driving licence and passport numbers.

The theft from Optus of personal data which, my understanding is, they are required to hold for security reasons – for example, in the event a smartphone card was used to trigger a bomb – has led to a varied media response.

Personally, it prompted a recollection of an evening in 2013 when I called in on a meeting of a local location-based marketing group in Singapore, and learned of experiments government-owned Singtel – which owns Optus – had been conducting in Australia.

Behavioural data scientist Ewa Szymanska, who was working in Singtel’s living analytics R&D lab, said that – with their consent – the movements of 500 Optus mobile phone users in Sydney had been tracked using GPS data. “We wanted to see if we could identify their lifestyle, and predict what their movements would be,” she says.

And they could, mapping work and leisure travel which showed everything from Thursday shopping trips to visits to entertainment venues and casinos, which petrol brands they bought and where they took a break.

Progressively, it was possible to group participants and pitch specific offers to them. Later Australian Claire Mula and others speculated how big a discount it would take to get someone driving near the airport to divert to a store in Jurong.

Mula – who had come from a data role at Fairfax Media to launch a marketing business called Sprooki, sold in 2017 for $10 million – reckoned one certainty was an increasingly targetted, data-driven pitch “in the not-very-distant future”.

Perhaps another might have been that it would only be a matter of time before such data was held to ransom.

Peter Coleman