Mastodon

Mastodon is a decentralized social network: instead of one company running one site, thousands of independent servers run the same software and connect to each other, so an account on one can follow and reply to accounts on any other.

That structure means no single operator sets the rules for everyone — moderation policy belongs to whichever server you join, and choosing one is effectively choosing a community and a set of norms.

The trade-off is friction: signing up requires picking a server, discovery is weaker than on centralized platforms, and reach is smaller. Its appeal is control and the absence of an advertising-driven algorithm, not scale.