This is one of the items that is tested in your Windows 8 App when you use the WACK.
If you are in Southern California, please email these posts for more information on getting a token for your app by June 30, 2012!
Properly handles activation from contracts, secondary tiles, and notifications
When an app is activated from a share contract, search contract, tile, or notification, parameters and data are passed to your app. Your app should retrieve the data at launch and act upon it.