A method of annotating an electronic message executes at a computing device having one or more processors and memory. The memory stores one or more programs configured for execution by the one or more processors. The device displays a user interface for an electronic messaging application. The user interface includes a list of messages received by the user, and each displayed message includes a respective message summary that is displayed. The device receives from the user a description of a first task associated with a first message of the displayed messages. The user provides the description using a control in the user interface. The device stores the description as a first annotation associated with the first message and updates the displayed messages in the list of messages. For the first message, the device displays the first annotation as a substitute for the message summary.