One of the most acute problems with centralized platforms is the need to develop one-size-fits-all moderation policies for billions of users. Decentralizing moderation puts decisions about what content to block or allow in the hands of users and communities.
Each server admin can create their own moderation rules as well as a theme for their server. Their TOS may include rules about whether data can leave the server, etc.
User level moderation allows users to opt into different content preferences, for example subscribing to shared blocklists, or enabling certain filters.
# Mastodon
Users choose which server to join, opting into the moderation policy, theme, and TOS they prefer.