The world's biggest digital companies will have nowhere to hide starting Friday, when the toughest EU rules on online content since social media first burst onto the scene enter into force.

The landmark law is part of the European Union's legal arsenal deployed to bring tech companies to heel and enforce order in what officials have described as an online "Wild West."

The Digital Services Act (DSA) forces companies to more aggressively police digital content and protect online users from disinformation and hate speech, or face the risk of heavy fines.