Abstract: A system and method are described for caching email messages within a data service. For example, a computer-implemented method according to one embodiment of the invention comprises: retrieving a first set of email messages from a first email server on behalf of a wireless data processing device; extracting metadata from the first set of email messages; storing the metadata in a first cache, the first cache managed according to a first cache management policy; storing at least the message bodies of the email messages in a second cache, the second cache managed according to a second cache management policy.

Abstract: A computer-implemented system and method for synchronizing email messages between an external email server a local email server and a wireless data processing device. For example, one embodiment of a system comprises a task queue comprised of a plurality of task entries, each entry associated with a particular user email account on the external email server and/or the local email server and representing a task to be performed in relation to the user email account; and a synchronizer to read synchronization tasks from the task queue and cause the synchronization tasks to be executed to synchronize email data stored on the external email server, the local email server and the wireless data processing device.