There's a new way that advertisers could track you around the web, and you might be surprised about where the tracking data would come from: your device's accelerometer. According to SFGate, security researcher Hristo Bojinov has discovered a way to distinguish individual devices simply by looking at data their accelerometers provide to webpages. Because accelerometers work imperfectly, they all display a unique result when idle — that result, Bojinov says, is enough to track a device around the web.

This is far from the only tracking tool advertisers have

A website would just need to implement a small piece of code in order to begin tracking a device this way, reports SFGate. Though Bojinov can't say for certain whether anyone is already doing this, he says he'd be surprised if an advertiser wasn't already exploring the possibility. To see how effective the method is, you can view your own mobile device's accelerometer footprint at a website set up by Stanford, where Bojinov is a PhD candidate in computer science. While you'll have to actively flip the phone around in order to make it work, that reportedly wouldn't be necessary for actual tracking.

Bojinov's research should be published in the coming months, SFGate reports. But while he may describe a surprising and eerie way to track devices, it's far from the only tool advertisers have for tracking: even outside of cookies, advertisers can distinguish between different people just by looking at information their browsers always hand over, like what fonts they have access to and what operating system is being used. That means accelerometer tracking may not be needed, but as advertisers look for better ways to follow people around the mobile web, it's easy to imagine that the option won't be ruled out.