I have been addicted to Apple’s Push Notification Service ever since I bought Prowl. There are endless possibilities on what you can do with Push Notifications.

The Apple Push Notification Service is a mobile service created by Apple Inc. that was released with iPhone OS 3.0 on the 17th June 2009. It uses push technology through a constantly-open IP connection to forward notifications from the servers of third party applications to the iPhone or iPod Touch; such notifications may include badges, sounds or custom text alerts.


Apple's Push Notification Announcement
Apple’s Push Notification Announcement