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The Windows Phone Store has two major new features with the update. First is a universal search which offers results of apps and how-to articles. The second one is the ability to install apps from an SD card, which allows you to download the XAP file for an app from the web portal, copy it to an SD card and then install it on your device. The only catch is that it has to be the newest version of the app or else it wont be compatible.
Another new feature with the update is the ability to choose apps from the My Phone link on the web portal and reinstall them to your device. This feature can be quite useful if you switch phones, but could take up some time to manually install each app.
source – Microsoft