Take Control of Your iPhone, 2nd Edition

Use Push, Fetch, or Manual?

When you set up MobileMe, for each type of data that you plan to sync, you'll need to decide whether to sync via Push or Fetch, or you can sync all your data manually.

With MobileMe, push refers to the ability to send data almost instantly from MobileMe to your iPhone (and vice versa), rather than at a specified interval, or via a manual command. It's active 24/7. With Push enabled for email, the iPhone notifies you when a new message arrives, via a sound and a text alert on the Home screen. In contrast, you don't receive update notices for other types of data; instead, you open a relevant app to see updates (for instance, you might see updated Contact data in Contacts or Maps). However, the updates occur automatically, ...