The problem here is Canvas fingerprinting - that's what I found the most surprising and interesting.

How do you prevent that, apart from working on 'fixing' browsers to create pixel-perfect renders across different browsers/platforms/configurations. Would that even be possible?

Edit:

> Tor Browser notifies the user for canvas read attempts and provides the option to return blank image data to prevent fingerprinting.

Huh. I guess that's one attempt, but being able to read pixel data out of a canvas is completely reasonable.