What’s scary is all of the ways they can track you even without your browser actively cooperating. For example, they can create an HTML5 canvas, render a bunch of shapes, and then probe individual pixels to get a read on your graphics card and drivers. The EFF has a very educational test you can subject your browser to in order to see how easy it is to fingerprint it based on these kinds of things.
What’s scary is all of the ways they can track you even without your browser actively cooperating. For example, they can create an HTML5 canvas, render a bunch of shapes, and then probe individual pixels to get a read on your graphics card and drivers. The EFF has a very educational test you can subject your browser to in order to see how easy it is to fingerprint it based on these kinds of things.