content: They are a step in the right direction, but blocking or faking just the canvas data blurs the fingerprint only slightly. If a site registers 10 visits with random or blocked canvases but with otherwise identical fingerprints, it's trivial to conclude that they're all the same person. Simple canvas blocking will become more effective as more people start doing it, but we need more robust anti-fingerprinting add-ons that fake as many other characteristics as possible, allowing your browser to truly blend into the crowd.