The accelerometer motion sensors within most smartphones could potentially be used to track the web activity of individual device owners, it has been claimed.

Stanford University phD student Hristo Bojinov says that because the accelerometers work 'imperfectly' they provide a unique ID when idle. That's potentially enough for advertisers to follow users around the web.

According to Bojinov, the method is similar to the 'cookie' files that are used to track web activity, except, unlike cookies, the accelerometer data cannot to switched off or disabled by the user.

The researcher said he was unaware of whether marketeers or advertisers had already exploited the loophole, but would be surprised if the possibility wasn't already being investigated.

See for yourself...

The 'alarming' discovery is part of research investigated whether the various sensors sitting within smartphones can be used for tracking purposes and will be published in the coming months.

To illustrate its findings, the team of researchers has set up a website, showing users how they can generate their unique sensor ID data.

The method involves navigating to the Sensor-ID.com site, touching the screen, flipping it face down and flipping it back to reveal the identifying numbers. Repeating the experiment generates identical (or very similar numbers).

"People need to consider the whole system when they think about privacy," Bjinov told the SFGate site.

Via TheVerge