A method of presenting a unified view of two mailboxes, each mailbox associated with a client is described. The unified view allows the user to see all actions she/he performed on a message in one mailbox performed in all other unified mailboxes. One of the clients has both a high cost, e.g. wireless, communication channel and a low cost, e.g. synchronization, communication channel. When a message is received by a client from its respective mailbox without an identifier, an identifier is generated and a copy of the message is sent to the other mailboxes with the identifier. When the user performs actions on a message with a client, the identifier for the message and the action can be conveyed to the other clients in a message to the other mailboxes. The unified view can be selectably updated either over the high cost communication channel or the low cost communication channel. The presence of two communication channels enables the cost of performing the unification to be contained. The user can select options to control the unification process and the use of the high cost communication channel, e.g. summarize messages over 250 words and/or remove attachments.