Digital millennium copyright act. It effectively moved the burden of proof for copyright infringement from the copyright owner to the accused, short-circuiting the existing IP laws, among other things.

It is where much of the drama around copyright online stems from. It’s used as a way to quickly stifle anything someone posts that’s something you don’t like.

It made circumventing DRM itself illegal, even if you’re not breaking copyright by doing so (even if it’s for your own research or backups).