People could auto-trust those who have been trusted by those they trust; this could have a user setting deciding how many degrees of separation they are willing

People could auto-trust those who have been trusted by those they trust; this could have a user setting deciding how many degrees of separation they are willing to trust. Everybody's public key (ie. the ability to read their signed posts) is public, it's a question of which ones you choose to read. There are many ways to skin this cat, but every one that's gonna work involves cooperation, rather than adversarial control.