Here is a list of all the Default views and what they mean:
Open: This lists all open conversations.
Mentioned: The list of all open conversations where the logged-in agent is mentioned in some note.
Assigned to me - This lists all open conversations assigned to the logged-in agent.
Unassigned - This lists all open conversations that are not assigned to any agent.
Assigned - This lists all open conversations that are assigned to some agent.
Closed - This lists all closed conversations.