Smartphones have a lot to say about their owners, delighting advertisers and stirring up privacy fears We're observing your behaviours and connecting your profile to mobile devices. Once, only hairdressers and bartenders knew people's secrets. Now, smartphones know everything - where people go, what they search for, what they buy, what they do for fun and when they go to bed. That is why advertisers, and tech companies such as Google and Facebook, are finding new, sophisticated ways to track people on their phones and reach them with individualised, hypertargeted ads. And they are doing it without cookies, those tiny bits of code that follow users around the internet, because cookies do not work on mobile devices. Privacy advocates fear consumers do not realise just how much of their private information is on their phones and how much is made vulnerable simply by downloading and using apps, searching the mobile web or even just going about daily life with a phone in your pocket. And this new focus on tracking users through their devices and online habits comes against the backdrop of a spirited public debate on privacy and government surveillance. On Wednesday, the US National Security Agency confirmed it had collected data from cellphone towers in 2010 and 2011 to locate Americans' mobiles, though it said it never used the information. "People don't understand tracking, whether it's on the browser or mobile device, and don't have any visibility into the practices going on," said Jennifer King, who studies privacy at the University of California, Berkeley, and has advised the US Federal Trade Commission on mobile tracking. Drawbridge is one of several start ups that has figured out how to follow people without cookies, and to determine that a cellphone, work computer, home computer and tablet belong to the same person, even if the devices are in no way connected. "We're observing your behaviours and connecting your profile to mobile devices," said Eric Rosenblum, chief operating officer at Drawbridge. But don't call it tracking. "Tracking is a dirty word," he said. Drawbridge, founded by a former Google data scientist, says it has matched 1.5 billion devices this way, allowing it to deliver mobile ads based on websites the person has visited on a computer. If you research a Hawaiian vacation on your work desktop, you could see a Hawaii ad that night on your mobile phone. For advertisers, intimate knowledge of users has long been the promise of mobile phones. But only now are many mobile advertising services exploiting that knowledge, largely based on monitoring the apps we use and the places we go. "In the old days of ad targeting, we give them a list of sites and we'd say 'Women 25 to 45'," said e-commerce manager David Katz. In the new age, we basically say 'Go get us users'.