Glossary
Watermark
A watermark embeds a marker, visible or imperceptible, into a piece of shared content that's unique to the specific copy given to a specific recipient. If that copy later leaks, the embedded marker can identify which recipient's copy it was, even when the leaked content otherwise looks identical to every other copy that was distributed.
This doesn't prevent a leak from happening — it changes the incentive around leaking in the first place, since a recipient aware that their specific copy is traceable back to them faces a real, personal consequence for being the source, rather than the comfortable anonymity of one indistinguishable copy among many identical ones.