What is the sharing model for Experience Cloud communities?

Experience Cloud uses two key sharing mechanisms for external users:

1. Sharing Sets — grant Read or Edit access to records by matching a field on the record to the external user's profile-associated account or contact (e.g., Account lookup on Case matches the user's Account). Sharing Sets are the primary way to give Customer Community users access to their own records.
2. Share Groups — a public group containing all users of a specific community profile; used with manual or criteria-based sharing rules to expand record access beyond sharing sets. Standard Salesforce sharing rules, role hierarchy (communities have a limited role hierarchy), and Apex Sharing also apply. External users cannot own records in Customer Community licenses; Partner Community users can own records (Opportunities, Leads).