18. A server that sends a message expressing a statement on behalf of a user, the server comprising: a processor; and a memory storing: an expression set comprising at least one expression authored by the user; and instructions that, when executed by the processor, provide: an expression style identifier that examines the expression set to identify a phrase that appears in at least one prior expression previously authored by the user and that is relevant to the statement; and a message composer that: composes a message expressing the statement in an expression style of the user by: selecting a message template associated with the expression style of the user, wherein the message template comprises at least one slot for insertion of content to adapt the message template to the statement; and inserting the phrase previously authored by the user into the at least one message slot of the message template; presents the message to the user for confirmation; and responsive to receiving a confirmation of the message from the user, transmits the message to the recipient.
18. A server that sends a message expressing a statement on behalf of a user, the server comprising: a processor; and a memory storing: an expression set comprising at least one expression authored by the user; and instructions that, when executed by the processor, provide: an expression style identifier that examines the expression set to identify a phrase that appears in at least one prior expression previously authored by the user and that is relevant to the statement; and a message composer that: composes a message expressing the statement in an expression style of the user by: selecting a message template associated with the expression style of the user, wherein the message template comprises at least one slot for insertion of content to adapt the message template to the statement; and inserting the phrase previously authored by the user into the at least one message slot of the message template; presents the message to the user for confirmation; and responsive to receiving a confirmation of the message from the user, transmits the message to the recipient. 19. The server of claim 18 , wherein: the statement is associated with a content item; and the message composer composes the message expressing the statement by: identifying a selected content item that is associated with the statement; and composing the message including the selected content item in the message.