Here's a problem that every trust and safety team eventually runs into: predators don't stay on one platform. A person who is caught grooming children on Platform A, banned, and deleted — simply opens an account on Platform B. Platform B has no way of knowing. Platform B's moderation team starts from zero. The predator has a clean slate. This isn't a hypothetical. It's documented behavior. In the child safety space, researchers have consistently found that serial offenders operate across multiple platforms simultaneously, maintaining different personas for different targets. When one platform bans an account, another platform absorbs the risk. The obvious solution is for platforms to share information. But sharing information between platforms creates serious privacy problems. How do you tell Platform B about a threat without giving Platform B access to Platform A's users' private communications? This is the federation problem, and solving it correctly is genuinely difficult.…