1. A method for presenting notifications, comprising: at a computer system: obtaining message information, 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 includes 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.