19. A non-transitory computer readable storage medium storing one or more programs for execution by the one or more processors of a computer system, the one or more programs comprising instructions for: receiving message information from a server system, the message information representing a set of messages, and an importance score associated with each respective message in the set of messages, wherein the importance score is generated based at least in part on a global importance prediction model, and a user importance prediction model; in accordance with a determination that the set of messages include one or more unread priority messages, wherein priority messages comprise messages with which the associated importance score satisfy one or more predefined message importance criteria: presenting a new mail notification, wherein the global importance prediction model includes a social graph-related weight, the user importance prediction model is based on information associated with a single user, and the global importance prediction model is based on information associated with a plurality of users.
19. A non-transitory computer readable storage medium storing one or more programs for execution by the one or more processors of a computer system, the one or more programs comprising instructions for: receiving message information from a server system, the message information representing a set of messages, and an importance score associated with each respective message in the set of messages, wherein the importance score is generated based at least in part on a global importance prediction model, and a user importance prediction model; in accordance with a determination that the set of messages include one or more unread priority messages, wherein priority messages comprise messages with which the associated importance score satisfy one or more predefined message importance criteria: presenting a new mail notification, wherein the global importance prediction model includes a social graph-related weight, the user importance prediction model is based on information associated with a single user, and the global importance prediction model is based on information associated with a plurality of users. 24. The non-transitory computer readable storage medium of claim 19 , wherein the one or more programs further comprise instructions for: displaying the one or more unread priority messages in a portion of a display that is separate from a portion of the display used to display messages that fail to satisfy one or more predefined message importance criteria.