alt Hacker NewsUnfortunately, the swarm is 99.99999% advertisements for penis enlargement pills. How can a P2P system filter them out? A federated system relies on each admin to filter them out. A centralised system does even better, relying on a single dictator to filter them out. A P2P system requires every user to filter every spam message, together consuming far more effort than the spammer needed to send it.
This isn't, and has never been a hard problem. Just pay for people's attention. People you follow don't have to pay, and make that transitive. Penalize people in your network who propagate spam by increasing the cost to get your attention.