Insurance is one example. Privacy experts warn that detailed information on personal lifestyles – gathered from sites such as Google, Facebook and many other sources – will soon be used to decide how much individuals pay for their health insurance.
Katina Michael, associate professor of information systems and technology at Wollongong University, says global companies with intimate details on the lives of hundreds of millions of people are already establishing their own insurance arms.
"Your health insurance will go up because data being stored about you on the cloud will show you're not doing enough exercise and are buying lots of fatty foods," she says. "Your future health provider may well be a subsidiary of Google, Samsung or Microsoft."
Michael says that along with its massive surveillance capacity, Google has invested in 23andMe, a company that tells people how their future health may be influenced by their genetics. Hundreds of thousands of people have already given their DNA to this company, she says.
"You might realise your personal details are being harvested but you don't know how the companies storing your data are enmeshed in the background, the alliances and partnerships they have. You don't know these things."
Personal security is another downside. For instance, GPS location data gathered from mobile phones, cloud storage of home addresses, and online chats about holiday plans are in the everyday burglar's toolkit.
According to a study by British security firm Friedland, 78 per cent of burglars use social media such as Facebook and Twitter to get status updates and to target properties. Google Street View also allows them to plan break-ins from the comfort of their own homes.