A (relatively) new tracking technique called canvas fingerprinting allows websites and services to uniquely identify people’s devices by including a hidden image on web pages. It can get around most of the common methods and tools people use to keep their activities from being tracked (though it works less well on mobile devices). New anti-tracking methods and tools will doubtless be devised to foil it — but then a new tracking technique will come along!

We do recommend using anti-tracking tools if you don’t want records of all your Internet activities to be linked together — they will help protect you against some forms of tracking — but it’s always safest to assume that somebody may still be able to figure out exactly who you are.