Patterns — separate
Anonymous Reputation-based Blacklisting
Get rid of troublemakers without even knowing who they are.
User data confinement pattern
Avoid the central collection of personal data by shifting some amount of the processing of personal data to the user-trusted environments (e.g. their own devices). Allow users to control the exact data that shares with service providers
Personal Data Store
Subjects keep control on their personal data that are stored on a personal device.