Ad networks recognise you without cookies: by your graphics card, your fonts, your audio output. AdSilence blurs that trail.
Graphics, 3D and audio values come back slightly changed each time. Within one site they stay stable so nothing breaks; between two sites they no longer match.
Cover Your Tracks, run by the Electronic Frontier Foundation, reports a randomised fingerprint with AdSilence and awards full marks. Without the extension the same browser is nearly unique.
The services that collect fingerprints are blocked at the network level. What never loads cannot measure anything.