Apple seems to have already started rolling out their cloud service by incorporating a quiet update in the iTunes App Store on their iOS devices by adding a Purchased button. This new feature was announced in the keynote at WWDC 2011 which took place on the 6th of June. On iOS devices one can now see this new feature under the Updates tab in the App Store.
Purchased button appears in the App Store of certain Apple devices
When the Purchased option is tapped, one gets directed to a page with the Updates tab in the App Store where they are able to find two menus - one is a list of all the apps that a user has purchased, and the other listing shows the apps that one has purchased but have not yet been installed on the said Apple device.
This feature has been noticed on some iOS devices while other portable iOS devices are not displaying it. As soon as we get more details on the updated feature of the App Store we will let you know.
Do let us know in the comments if the feature is available for your device and if you find this new feature convenient.