After an initial beta period, the cc recipients feature has undergone quite some changes. Notifications are no longer tied to trigger notifications, and have been decoupled completely from the trigger system to ensure functional transparency. Cc recipients now receive a customized email for every comment update to a ticket. 

Cc Recipents are notified when they are on the cc list, and

• A ticket update contains a comment 
  
• The cc recipient is not notified by any trigger 
  
• The cc recipient is not author of the comment

Agent recipients receive all updates. End-user recipients only receive public updates.

When a ticket is created by email, Zendesk evaluates all other recipients in that email (both To: and Cc: recipients) and makes them cc recipients on future ticket updates,.

These rules still apply:

• An end-user can add cc recipients any time during a ticket's lifetime.
  
• Only agents can delete cc recipients once they're added.
  
• Agents can only cc already existing end-users.
  
• Agents can also add other agents as cc recipients.
  
• Cc'ed agents will receive copies of all agent notifications
  
• When cc'ing unknown end-users in an open help desk, the new users will be created automatically.